Complete the square

A question is this type if and only if it asks to express a quadratic in the form a(x+b)²+c or similar completed square form, without further application.

43 questions · Moderate -0.9

1.02e Complete the square: quadratic polynomials and turning points
Sort by: Default | Easiest first | Hardest first
CAIE P1 2021 June Q1
4 marks Moderate -0.8
1
  1. Express \(16 x ^ { 2 } - 24 x + 10\) in the form \(( 4 x + a ) ^ { 2 } + b\).
  2. It is given that the equation \(16 x ^ { 2 } - 24 x + 10 = k\), where \(k\) is a constant, has exactly one root. Find the value of this root.
CAIE P1 2022 June Q1
4 marks Easy -1.2
1
  1. Express \(x ^ { 2 } - 8 x + 11\) in the form \(( x + p ) ^ { 2 } + q\) where \(p\) and \(q\) are constants.
  2. Hence find the exact solutions of the equation \(x ^ { 2 } - 8 x + 11 = 1\).
CAIE P1 2020 November Q1
4 marks Easy -1.2
1
  1. Express \(x ^ { 2 } + 6 x + 5\) in the form \(( x + a ) ^ { 2 } + b\), where \(a\) and \(b\) are constants.
  2. The curve with equation \(y = x ^ { 2 }\) is transformed to the curve with equation \(y = x ^ { 2 } + 6 x + 5\). Describe fully the transformation(s) involved.
CAIE P1 2021 November Q8
10 marks Moderate -0.8
8
  1. Express \(- 3 x ^ { 2 } + 12 x + 2\) in the form \(- 3 ( x - a ) ^ { 2 } + b\), where \(a\) and \(b\) are constants.
    The one-one function f is defined by \(\mathrm { f } : x \mapsto - 3 x ^ { 2 } + 12 x + 2\) for \(x \leqslant k\).
  2. State the largest possible value of the constant \(k\).
    It is now given that \(k = - 1\).
  3. State the range of f.
  4. Find an expression for \(\mathrm { f } ^ { - 1 } ( x )\).
    The result of translating the graph of \(y = \mathrm { f } ( x )\) by \(\binom { - 3 } { 1 }\) is the graph of \(y = \mathrm { g } ( x )\).
  5. Express \(\mathrm { g } ( x )\) in the form \(p x ^ { 2 } + q x + r\), where \(p , q\) and \(r\) are constants.
CAIE P1 2021 November Q3
5 marks Moderate -0.8
3
  1. Express \(5 y ^ { 2 } - 30 y + 50\) in the form \(5 ( y + a ) ^ { 2 } + b\), where \(a\) and \(b\) are constants.
  2. The function f is defined by \(\mathrm { f } ( x ) = x ^ { 5 } - 10 x ^ { 3 } + 50 x\) for \(x \in \mathbb { R }\). Determine whether \(f\) is an increasing function, a decreasing function or neither.
CAIE P1 2022 November Q6
9 marks Easy -1.2
6 The equation of a curve is \(y = 4 x ^ { 2 } + 20 x + 6\).
  1. Express the equation in the form \(y = a ( x + b ) ^ { 2 } + c\), where \(a\), \(b\) and \(c\) are constants.
  2. Hence solve the equation \(4 x ^ { 2 } + 20 x + 6 = 45\).
  3. Sketch the graph of \(y = 4 x ^ { 2 } + 20 x + 6\) showing the coordinates of the stationary point. You are not required to indicate where the curve crosses the \(x\) - and \(y\)-axes.
CAIE P1 2015 June Q1
3 marks Easy -1.2
1 Express \(2 x ^ { 2 } - 12 x + 7\) in the form \(a ( x + b ) ^ { 2 } + c\), where \(a , b\) and \(c\) are constants.
CAIE P1 2018 June Q1
3 marks Easy -1.2
1 Express \(3 x ^ { 2 } - 12 x + 7\) in the form \(a ( x + b ) ^ { 2 } + c\), where \(a , b\) and \(c\) are constants.
CAIE P1 2019 June Q5
6 marks Moderate -0.8
5 The function f is defined by \(\mathrm { f } ( x ) = - 2 x ^ { 2 } + 12 x - 3\) for \(x \in \mathbb { R }\).
  1. Express \(- 2 x ^ { 2 } + 12 x - 3\) in the form \(- 2 ( x + a ) ^ { 2 } + b\), where \(a\) and \(b\) are constants.
  2. State the greatest value of \(\mathrm { f } ( x )\).
    The function g is defined by \(\mathrm { g } ( x ) = 2 x + 5\) for \(x \in \mathbb { R }\).
  3. Find the values of \(x\) for which \(\operatorname { gf } ( x ) + 1 = 0\).
CAIE P1 2015 November Q3
6 marks Moderate -0.8
3
  1. Express \(3 x ^ { 2 } - 6 x + 2\) in the form \(a ( x + b ) ^ { 2 } + c\), where \(a , b\) and \(c\) are constants.
  2. The function f , where \(\mathrm { f } ( x ) = x ^ { 3 } - 3 x ^ { 2 } + 7 x - 8\), is defined for \(x \in \mathbb { R }\). Find \(\mathrm { f } ^ { \prime } ( x )\) and state, with a reason, whether f is an increasing function, a decreasing function or neither.
CAIE P1 Specimen Q9
8 marks Moderate -0.8
9
  1. Express \(- x ^ { 2 } + 6 x - 5\) in the form \(a ( x + b ) ^ { 2 } + c\), where \(a , b\) and \(c\) are constants.
    The function \(\mathrm { f } : x \mapsto - x ^ { 2 } + 6 x - 5\) is defined for \(x \geqslant m\), where \(m\) is a constant.
  2. State the smallest value of \(m\) for which f is one-one.
  3. For the case where \(m = 5\), find an expression for \(\mathrm { f } ^ { - 1 } ( x )\) and state the domain of \(\mathrm { f } ^ { - 1 }\). \includegraphics[max width=\textwidth, alt={}, center]{097c5d00-9f92-4c3e-8056-7de09347fbb6-16_771_636_260_756} The diagram shows a cuboid \(O A B C P Q R S\) with a horizontal base \(O A B C\) in which \(A B = 6 \mathrm {~cm}\) and \(O A = a \mathrm {~cm}\), where \(a\) is a constant. The height \(O P\) of the cuboid is 10 cm . The point \(T\) on \(B R\) is such that \(B T = 8 \mathrm {~cm}\), and \(M\) is the mid-point of \(A T\). Unit vectors \(\mathbf { i } , \mathbf { j }\) and \(\mathbf { k }\) are parallel to \(O A , O C\) and \(O P\) respectively.
Edexcel P1 2023 June Q3
6 marks Moderate -0.8
  1. (a) Express \(3 x ^ { 2 } + 12 x + 13\) in the form
$$a ( x + b ) ^ { 2 } + c$$ where \(a\), \(b\) and \(c\) are integers to be found.
(b) Hence sketch the curve with equation \(y = 3 x ^ { 2 } + 12 x + 13\) On your sketch show clearly
  • the coordinates of the \(y\) intercept
  • the coordinates of the turning point of the curve
Edexcel P1 2022 October Q9
14 marks Standard +0.3
9. \begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{db979349-3415-420f-a39f-8cc8c24a69d0-24_889_666_258_703} \captionsetup{labelformat=empty} \caption{Figure 3}
\end{figure} Figure 3 shows a sketch of the curve \(C\) with equation $$y = \frac { 1 } { 2 } x ^ { 2 } - 10 x + 22$$
  1. Write \(\frac { 1 } { 2 } x ^ { 2 } - 10 x + 22\) in the form $$a ( x + b ) ^ { 2 } + c$$ where \(a , b\) and \(c\) are constants to be found. The point \(M\) is the minimum turning point of \(C\), as shown in Figure 3.
  2. Deduce the coordinates of \(M\) The line \(l\) is the normal to \(C\) at the point \(P\), as shown in Figure 3.
    Given that \(l\) has equation \(y = k - \frac { 1 } { 8 } x\), where \(k\) is a constant,
    1. find the coordinates of \(P\)
    2. find the value of \(k\) Question 9 continues on the next page \begin{figure}[h]
      \includegraphics[alt={},max width=\textwidth]{db979349-3415-420f-a39f-8cc8c24a69d0-25_903_682_299_605} \captionsetup{labelformat=empty} \caption{Figure 4}
      \end{figure} Figure 4 is a copy of Figure 3. The finite region \(R\), shown shaded in Figure 4, is bounded by \(l , C\) and the line through \(M\) parallel to the \(y\)-axis.
  3. Identify the inequalities that define \(R\).
Edexcel C1 2005 January Q10
12 marks Easy -1.2
10. Given that $$\mathrm { f } ( x ) = x ^ { 2 } - 6 x + 18 , \quad x \geqslant 0 ,$$
  1. express \(\mathrm { f } ( x )\) in the form \(( x - a ) ^ { 2 } + b\), where \(a\) and \(b\) are integers. The curve \(C\) with equation \(y = \mathrm { f } ( x ) , x \geqslant 0\), meets the \(y\)-axis at \(P\) and has a minimum point at \(Q\).
  2. In the space provided on page 19, sketch the graph of \(C\), showing the coordinates of \(P\) and \(Q\). The line \(y = 41\) meets \(C\) at the point \(R\).
  3. Find the \(x\)-coordinate of \(R\), giving your answer in the form \(p + q \sqrt { } 2\), where \(p\) and \(q\) are integers.
Edexcel C1 2010 June Q4
6 marks Moderate -0.8
4. (a) Show that \(x ^ { 2 } + 6 x + 11\) can be written as $$( x + p ) ^ { 2 } + q$$ where \(p\) and \(q\) are integers to be found.
(b) In the space at the top of page 7 , sketch the curve with equation \(y = x ^ { 2 } + 6 x + 11\), showing clearly any intersections with the coordinate axes.
(c) Find the value of the discriminant of \(x ^ { 2 } + 6 x + 11\)
Edexcel C1 2017 June Q5
8 marks Easy -1.2
5. $$f ( x ) = x ^ { 2 } - 8 x + 19$$
  1. Express \(\mathrm { f } ( x )\) in the form \(( x + a ) ^ { 2 } + b\), where \(a\) and \(b\) are constants. The curve \(C\) with equation \(y = \mathrm { f } ( x )\) crosses the \(y\)-axis at the point \(P\) and has a minimum point at the point \(Q\).
  2. Sketch the graph of \(C\) showing the coordinates of point \(P\) and the coordinates of point \(Q\).
  3. Find the distance \(P Q\), writing your answer as a simplified surd.
OCR C1 2005 January Q2
4 marks Moderate -0.8
2 Given that \(2 x ^ { 2 } - 12 x + p = q ( x - r ) ^ { 2 } + 10\) for all values of \(x\), find the constants \(p , q\) and \(r\).
OCR C1 2006 January Q5
7 marks Moderate -0.8
5
  1. Express \(x ^ { 2 } + 3 x\) in the form \(( x + a ) ^ { 2 } + b\).
  2. Express \(y ^ { 2 } - 4 y - \frac { 11 } { 4 }\) in the form \(( y + p ) ^ { 2 } + q\). A circle has equation \(x ^ { 2 } + y ^ { 2 } + 3 x - 4 y - \frac { 11 } { 4 } = 0\).
  3. Write down the coordinates of the centre of the circle.
  4. Find the radius of the circle.
OCR C1 2007 January Q6
6 marks Moderate -0.8
6
  1. Express \(2 x ^ { 2 } - 24 x + 80\) in the form \(a ( x - b ) ^ { 2 } + c\).
  2. State the equation of the line of symmetry of the curve \(y = 2 x ^ { 2 } - 24 x + 80\).
  3. State the equation of the tangent to the curve \(y = 2 x ^ { 2 } - 24 x + 80\) at its minimum point.
OCR C1 2005 June Q2
5 marks Moderate -0.8
2
  1. Express \(3 x ^ { 2 } + 12 x + 7\) in the form \(3 ( x + a ) ^ { 2 } + b\).
  2. Hence write down the equation of the line of symmetry of the curve \(y = 3 x ^ { 2 } + 12 x + 7\).
OCR C1 2007 June Q1
3 marks Easy -1.8
1 Simplify \(( 2 x + 5 ) ^ { 2 } - ( x - 3 ) ^ { 2 }\), giving your answer in the form \(a x ^ { 2 } + b x + c\).
OCR C1 Q8
10 marks Moderate -0.8
8. $$f ( x ) = 9 + 6 x - x ^ { 2 } .$$
  1. Find the values of \(A\) and \(B\) such that $$\mathrm { f } ( x ) = A - ( x + B ) ^ { 2 }$$
  2. State the maximum value of \(\mathrm { f } ( x )\).
  3. Solve the equation \(\mathrm { f } ( x ) = 0\), giving your answers in the form \(a + b \sqrt { 2 }\) where \(a\) and \(b\) are integers.
  4. Sketch the curve \(y = \mathrm { f } ( x )\).
OCR C1 2009 January Q6
8 marks Moderate -0.8
6
  1. Express \(5 x ^ { 2 } + 20 x - 8\) in the form \(p ( x + q ) ^ { 2 } + r\).
  2. State the equation of the line of symmetry of the curve \(y = 5 x ^ { 2 } + 20 x - 8\).
  3. Calculate the discriminant of \(5 x ^ { 2 } + 20 x - 8\).
  4. State the number of real roots of the equation \(5 x ^ { 2 } + 20 x - 8 = 0\).
OCR C1 2010 January Q1
3 marks Easy -1.2
1 Express \(x ^ { 2 } - 12 x + 1\) in the form \(( x - p ) ^ { 2 } + q\).
OCR C1 2009 June Q7
6 marks Moderate -0.8
7
  1. Express \(x ^ { 2 } - 5 x + \frac { 1 } { 4 }\) in the form \(( x - a ) ^ { 2 } - b\).
  2. Find the centre and radius of the circle with equation \(x ^ { 2 } + y ^ { 2 } - 5 x + \frac { 1 } { 4 } = 0\).