# Past Papers’ Solutions | Cambridge International Examinations (CIE) | AS & A level | Mathematics 9709 | Pure Mathematics 1 (P1-9709/01) | Year 2017 | Feb-Mar | (P1-9709/12) | Q#2

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**Question**

In the expansion of , the coefficient of x is 5. Find the value of the constant a.

**Solution**

We are given expression as;

Expression for the general term in the Binomial expansion of is:

In the given case:

Hence;

Since we are looking for the terms with i.e. we can equate;

Now we can find the term with; Substituting ;

We are given that the coefficient of x is 5. Therefore;

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