AQA Paper 3 2021 June — Question 6 4 marks

Exam BoardAQA
ModulePaper 3 (Paper 3)
Year2021
SessionJune
Marks4
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicIndices and Surds
TypeSimplify algebraic expressions with indices
DifficultyStandard +0.3 This is a straightforward algebraic manipulation requiring factorisation of the numerator by grouping terms and recognising common factors involving surds. While it requires careful algebraic handling of fractional powers and multiple steps, it follows standard A-level techniques without requiring novel insight—slightly easier than average due to being a pure manipulation exercise.
Spec1.02a Indices: laws of indices for rational exponents1.02b Surds: manipulation and rationalising denominators1.02k Simplify rational expressions: factorising, cancelling, algebraic division

Given that \(x > 0\) and \(x \neq 25\), fully simplify $$\frac{10 + 5x - 2x^{\frac{1}{2}} - x^{\frac{3}{2}}}{5 - \sqrt{x}}$$ Fully justify your answer. [4 marks]

Question 6:
AnswerMarks
6Begins to solve the problem
using an appropriate technique
eg factorising or grouping terms
in numerator or writing y= x
PI if 2 + x or 25 – x or
5 – x1/2 seen
or
5+ x
multiplies by
AnswerMarks Guidance
5+ x3.1a M1
10+5x−2x2−x2 5+ x
×
5− x 5+ x
1 3 3
50+25x−10x2−5x2+10 x+5x x−2x−x2 x
=
25−x
50+23x−x2
=
25−x
(25−x)(2+x)
=
25−x
=2+x
Obtains one correct common
factor in numerator eg 2 + x or
25 – x or 5 – x1/2
or
expands numerator
condone one error
AnswerMarks Guidance
may be unsimplified1.1a M1
Obtains second correct common
factor in numerator
or
obtains correct simplified
numerator and denominator
AnswerMarks Guidance
PI in long division1.1a M1
Completes manipulation by
cancelling common factor to
AnswerMarks Guidance
obtain 2 + x1.1b A1
Total4
QMarking instructions AO
Question 6:
6 | Begins to solve the problem
using an appropriate technique
eg factorising or grouping terms
in numerator or writing y= x
PI if 2 + x or 25 – x or
5 – x1/2 seen
or
5+ x
multiplies by
5+ x | 3.1a | M1 | 1 3
10+5x−2x2−x2 5+ x
×
5− x 5+ x
1 3 3
50+25x−10x2−5x2+10 x+5x x−2x−x2 x
=
25−x
50+23x−x2
=
25−x
(25−x)(2+x)
=
25−x
=2+x
Obtains one correct common
factor in numerator eg 2 + x or
25 – x or 5 – x1/2
or
expands numerator
condone one error
may be unsimplified | 1.1a | M1
Obtains second correct common
factor in numerator
or
obtains correct simplified
numerator and denominator
PI in long division | 1.1a | M1
Completes manipulation by
cancelling common factor to
obtain 2 + x | 1.1b | A1
Total | 4
Q | Marking instructions | AO | Mark | Typical solution
Given that $x > 0$ and $x \neq 25$, fully simplify
$$\frac{10 + 5x - 2x^{\frac{1}{2}} - x^{\frac{3}{2}}}{5 - \sqrt{x}}$$

Fully justify your answer.
[4 marks]

\hfill \mbox{\textit{AQA Paper 3 2021 Q6 [4]}}