Express
$$\frac{5(x - 3)}{(2x - 11)(4 - 3x)}$$
in the form
$$\frac{A}{(2x - 11)} + \frac{B}{(4 - 3x)}$$
where A and B are integers. - AQA - A-Level Maths Pure - Question 5 - 2021 - Paper 2
Question 5
Express
$$\frac{5(x - 3)}{(2x - 11)(4 - 3x)}$$
in the form
$$\frac{A}{(2x - 11)} + \frac{B}{(4 - 3x)}$$
where A and B are integers.
Worked Solution & Example Answer:Express
$$\frac{5(x - 3)}{(2x - 11)(4 - 3x)}$$
in the form
$$\frac{A}{(2x - 11)} + \frac{B}{(4 - 3x)}$$
where A and B are integers. - AQA - A-Level Maths Pure - Question 5 - 2021 - Paper 2
Step 1
Form the identity
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Answer
We start by writing the expression in the form of the equation:
(2x−11)(4−3x)5(x−3)=(2x−11)A+(4−3x)B.
Multiplying both sides by the denominator, we get:
5(x−3)=A(4−3x)+B(2x−11).
Step 2
Obtain A
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Answer
To find A, we can substitute a convenient value for x.
Letting ( x = \frac{4}{3} ), the equation simplifies as follows:
5(34−3)=A(4−3(34))+B(2(34)−11).
Simplifying, we find:
( A = -1 ).
Step 3
Obtain B
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Answer
Next, to find B, we substitute a different value for x.