Rationalize denominator simple

A question is this type if and only if it asks to rationalize a denominator of the form a/(b + c√d) or a/(b - c√d) by multiplying by the conjugate, resulting in the form p + q√r.

79 questions · Easy -1.1

1.02b Surds: manipulation and rationalising denominators
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Edexcel C1 2006 January Q5
6 marks Easy -1.8
5. (a) Write \(\sqrt { 45 }\) in the form \(a \sqrt { 5 }\), where \(a\) is an integer.
(b) Express \(\frac { 2 ( 3 + \sqrt { 5 } ) } { ( 3 - \sqrt { 5 } ) }\) in the form \(b + c \sqrt { 5 }\), where \(b\) and \(c\) are integers.
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\end{figure} Figure 1 shows a sketch of the curve with equation \(y = \mathrm { f } ( x )\). The curve passes through the points \(( 0,3 )\) and \(( 4,0 )\) and touches the \(x\)-axis at the point \(( 1,0 )\). On separate diagrams sketch the curve with equation
Edexcel C1 2011 January Q3
4 marks Easy -1.2
3. Simplify $$\frac { 5 - 2 \sqrt { 3 } } { \sqrt { 3 } - 1 }$$ giving your answer in the form \(p + q \sqrt { } 3\), where \(p\) and \(q\) are rational numbers.
Edexcel C1 2014 January Q1
4 marks Easy -1.2
  1. Simplify fully
    1. \(( 2 \sqrt { } x ) ^ { 2 }\)
    2. \(\frac { 5 + \sqrt { 7 } } { 2 + \sqrt { 7 } }\)
Edexcel C1 2006 June Q6
4 marks Easy -1.3
6. (a) Expand and simplify \(( 4 + \sqrt { 3 } ) ( 4 - \sqrt { 3 } )\).
(b) Express \(\frac { 26 } { 4 + \sqrt { 3 } }\) in the form \(a + b \sqrt { 3 }\), where \(a\) and \(b\) are integers.
Edexcel C1 2013 June Q1
4 marks Easy -1.2
  1. Simplify
$$\frac { 7 + \sqrt { 5 } } { \sqrt { 5 } - 1 }$$ giving your answer in the form \(a + b \sqrt { 5 }\), where \(a\) and \(b\) are integers.
Edexcel C1 2008 January Q3
4 marks Easy -1.3
Simplify $$\frac { 5 - \sqrt { 3 } } { 2 + \sqrt { 3 } } ,$$ giving your answer in the form \(a + b \sqrt { } 3\), where \(a\) and \(b\) are integers.
Edexcel C1 2010 January Q2
6 marks Easy -1.2
  1. Expand and simplify \(( 7 + \sqrt { 5 } ) ( 3 - \sqrt { 5 } )\).
  2. Express \(\frac { 7 + \sqrt { 5 } } { 3 + \sqrt { 5 } }\) in the form \(a + b \sqrt { 5 }\), where \(a\) and \(b\) are integers.
Edexcel C1 2012 January Q2
6 marks Easy -1.3
  1. Simplify $$\sqrt { } 32 + \sqrt { } 18$$ giving your answer in the form \(a \sqrt { } 2\), where \(a\) is an integer.
  2. Simplify $$\frac { \sqrt { } 32 + \sqrt { } 18 } { 3 + \sqrt { } 2 }$$ giving your answer in the form \(b \sqrt { } 2 + c\), where \(b\) and \(c\) are integers.
Edexcel C1 2016 June Q3
5 marks Easy -1.3
  1. Simplify $$\sqrt { 50 } - \sqrt { 18 }$$ giving your answer in the form \(a \sqrt { 2 }\), where \(a\) is an integer.
  2. Hence, or otherwise, simplify $$\frac { 12 \sqrt { 3 } } { \sqrt { 50 } - \sqrt { 18 } }$$ giving your answer in the form \(b \sqrt { c }\), where \(b\) and \(c\) are integers and \(b \neq 1\)
OCR C1 2007 January Q1
3 marks Easy -1.2
1 Express \(\frac { 5 } { 2 - \sqrt { 3 } }\) in the form \(a + b \sqrt { 3 }\), where \(a\) and \(b\) are integers.
OCR C1 2008 January Q1
3 marks Easy -1.2
1 Express \(\frac { 4 } { 3 - \sqrt { 7 } }\) in the form \(a + b \sqrt { 7 }\), where \(a\) and \(b\) are integers.
OCR C1 2005 June Q5
7 marks Easy -1.3
5
  1. Simplify \(2 x ^ { \frac { 2 } { 3 } } \times 3 x ^ { - 1 }\).
  2. Express \(2 ^ { 40 } \times 4 ^ { 30 }\) in the form \(2 ^ { n }\).
  3. Express \(\frac { 26 } { 4 - \sqrt { } 3 }\) in the form \(a + b \sqrt { } 3\).
OCR MEI C1 2008 January Q8
5 marks Easy -1.2
8
  1. Write \(\sqrt { 48 } + \sqrt { 3 }\) in the form \(a \sqrt { b }\), where \(a\) and \(b\) are integers and \(b\) is as small as possible.
  2. Simplify \(\frac { 1 } { 5 + \sqrt { 2 } } + \frac { 1 } { 5 - \sqrt { 2 } }\).
OCR MEI C1 2007 June Q8
5 marks Easy -1.2
8
  1. Simplify \(\sqrt { 98 } - \sqrt { 50 }\).
  2. Express \(\frac { 6 \sqrt { 5 } } { 2 + \sqrt { 5 } }\) in the form \(a + b \sqrt { 5 }\), where \(a\) and \(b\) are integers.
OCR MEI C1 2008 June Q7
5 marks Easy -1.2
7
  1. Express \(\frac { 1 } { 5 + \sqrt { 3 } }\) in the form \(\frac { a + b \sqrt { 3 } } { c }\), where \(a , b\) and \(c\) are integers.
  2. Expand and simplify \(( 3 - 2 \sqrt { 7 } ) ^ { 2 }\).
OCR MEI C1 Q8
5 marks Easy -1.2
8 Find the values of \(a\) and \(b\) for which \(\frac { 4 } { ( 2 \sqrt { 3 } - 1 ) } = a + b \sqrt { 3 }\).
OCR C1 Q2
3 marks Easy -1.2
  1. Express
$$\frac { 2 } { 3 \sqrt { 5 } + 7 }$$ in the form \(a + b \sqrt { 5 }\) where \(a\) and \(b\) are rational.
OCR MEI C1 Q4
5 marks Moderate -0.8
4
  1. Express \(125 \sqrt { 5 }\) in the form \(5 ^ { k }\).
  2. Simplify \(10 + 7 \sqrt { 5 } + \frac { 38 } { 1 - 2 \sqrt { 5 } }\), giving your answer in the form \(a + b \sqrt { 5 }\).
OCR MEI C1 Q5
5 marks Easy -1.2
5
  1. Express \(\sqrt { 48 } + \sqrt { 75 }\) in the form \(a \sqrt { b }\), where \(a\) and \(b\) are integers.
  2. Simplify \(\frac { 7 + 2 \sqrt { 5 } } { 7 + \sqrt { 5 } }\), expressing your answer in the form \(\frac { a + b \sqrt { 5 } } { c }\), where \(a , b\) and \(c\) are integers.
OCR MEI C1 Q9
5 marks Easy -1.2
9
  1. Express \(\sqrt { 48 } + \sqrt { 27 }\) in the form \(a \sqrt { 3 }\).
  2. Simplify \(\frac { 5 \sqrt { 2 } } { 3 - \sqrt { 2 } }\). Give your answer in the form \(\frac { b + c \sqrt { 2 } } { d }\).
OCR MEI C1 Q11
5 marks Easy -1.2
11
  1. Express \(\sqrt { 75 } + \sqrt { 48 }\) in the form \(a \sqrt { 3 }\).
  2. Express \(\frac { 14 } { 3 - \sqrt { 2 } }\) in the form \(b + c \sqrt { d }\).
OCR MEI C1 Q12
5 marks Easy -1.2
12
  1. Express \(\frac { 1 } { 5 + \sqrt { 3 } }\) in the form \(\frac { a + b \sqrt { 3 } } { c }\), where \(a , b\) and \(c\) are integers.
  2. Expand and simplify \(( 3 - 2 \sqrt { 7 } ) ^ { 2 }\).
OCR MEI C1 Q15
5 marks Easy -1.2
15
  1. Simplify \(\sqrt { 98 } \quad \sqrt { 50 }\).
  2. Express \(\frac { 6 \sqrt { 5 } } { 2 + \sqrt { 5 } }\) in the form \(a + b \sqrt { 5 }\), where \(a\) and \(b\) are integers.
OCR MEI C1 Q17
5 marks Easy -1.3
17
  1. Simplify \(5 \sqrt { 8 } + 4 \sqrt { 50 }\). Express your answer in the form \(a \sqrt { b }\), where \(a\) and \(b\) are integers and \(b\) is as small as possible.
  2. Express \(\frac { \sqrt { 3 } } { 6 \sqrt { 3 } }\) in the form \(p + q \sqrt { 3 }\), where \(p\) and \(q\) are rational.
Edexcel C1 2014 June Q6
5 marks Easy -1.2
6
  1. Write \(\sqrt { } 80\) in the form \(c \sqrt { } 5\), where \(c\) is a positive constant. A rectangle \(R\) has a length of ( \(1 + \sqrt { } 5\) ) cm and an area of \(\sqrt { 80 } \mathrm {~cm} ^ { 2 }\).
  2. Calculate the width of \(R\) in cm . Express your answer in the form \(p + q \sqrt { 5 }\), where \(p\) and \(q\) are integers to be found.