Solve p(algebraic transform) = 0

Questions where you solve p((y+c)^r) = 0 for rational exponents r (like (y+3)^(1/2) or (y-2)^2) by first solving p(x) = 0, then solving algebraic equations involving powers and roots.

7 questions · Standard +0.1

1.02f Solve quadratic equations: including in a function of unknown
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CAIE P3 2012 June Q3
7 marks Standard +0.3
3 The polynomial \(\mathrm { p } ( x )\) is defined by $$\mathrm { p } ( x ) = x ^ { 3 } - 3 a x + 4 a$$ where \(a\) is a constant.
  1. Given that \(( x - 2 )\) is a factor of \(\mathrm { p } ( x )\), find the value of \(a\).
  2. When \(a\) has this value,
    1. factorise \(\mathrm { p } ( x )\) completely,
    2. find all the roots of the equation \(\mathrm { p } \left( x ^ { 2 } \right) = 0\).
Edexcel P1 2020 January Q5
7 marks Standard +0.3
5. (a) Find, using algebra, all solutions of $$20 x ^ { 3 } - 50 x ^ { 2 } - 30 x = 0$$ (b) Hence find all real solutions of $$20 ( y + 3 ) ^ { \frac { 3 } { 2 } } - 50 ( y + 3 ) - 30 ( y + 3 ) ^ { \frac { 1 } { 2 } } = 0$$
Edexcel P1 2019 June Q5
7 marks Moderate -0.3
  1. (a) Find, using algebra, all real solutions of
$$2 x ^ { 3 } + 3 x ^ { 2 } - 35 x = 0$$ (b) Hence find all real solutions of $$2 ( y - 5 ) ^ { 6 } + 3 ( y - 5 ) ^ { 4 } - 35 ( y - 5 ) ^ { 2 } = 0$$
Edexcel P1 2021 June Q2
10 marks Standard +0.3
2. In this question you must show all stages of your working. Solutions relying on calculator technology are not acceptable. $$f ( x ) = a x ^ { 3 } + ( 6 a + 8 ) x ^ { 2 } - a ^ { 2 } x$$ where \(a\) is a positive constant. Given \(\mathrm { f } ( - 1 ) = 32\)
    1. show that the only possible value for \(a\) is 3
    2. Using \(a = 3\) solve the equation $$\mathrm { f } ( x ) = 0$$
  1. Hence find all real solutions of
    1. \(3 y + 26 y ^ { \frac { 2 } { 3 } } - 9 y ^ { \frac { 1 } { 3 } } = 0\)
    2. \(3 \left( 9 ^ { 3 z } \right) + 26 \left( 9 ^ { 2 z } \right) - 9 \left( 9 ^ { z } \right) = 0\)
Edexcel P1 2022 October Q4
6 marks Standard +0.3
  1. In this question you must show detailed reasoning. Solutions relying on calculator technology are not acceptable.
$$f ( x ) = x ^ { 2 } ( 2 x + 1 ) - 15 x$$
  1. Solve $$\mathrm { f } ( x ) = 0$$
  2. Hence solve $$y ^ { \frac { 4 } { 3 } } \left( 2 y ^ { \frac { 2 } { 3 } } + 1 \right) - 15 y ^ { \frac { 2 } { 3 } } = 0 \quad y > 0$$ giving your answer in simplified surd form.
Edexcel AS Paper 1 2021 November Q6
6 marks Standard +0.3
  1. In this question you should show all stages of your working.
Solutions relying on calculator technology are not acceptable.
  1. Using algebra, find all solutions of the equation $$3 x ^ { 3 } - 17 x ^ { 2 } - 6 x = 0$$
  2. Hence find all real solutions of $$3 ( y - 2 ) ^ { 6 } - 17 ( y - 2 ) ^ { 4 } - 6 ( y - 2 ) ^ { 2 } = 0$$
SPS SPS SM 2022 October Q7
6 marks Moderate -0.3
In this question you should show all stages of your working. Solutions relying on calculator technology are not acceptable.
  1. Using algebra, find all solutions of the equation $$3x^3 - 17x^2 - 6x = 0$$ [3]
  2. Hence find all real solutions of $$3(y - 2)^6 - 17(y - 2)^4 - 6(y - 2)^2 = 0$$ [3]