Competition problem — Algebra — Maths Olympiad Prep

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Algebra Difficulty 2.1 Junior Find the answer

If $x=2018$ , what is the value of the expression $x^{2}+2x-x(x+1)$ ?

Your answer

A number or a short expression. Spacing and $ signs are ignored.

Solution

For any value of $x$ , we have $x^{2}+2x-x(x+1)=x^{2}+2x-x^{2}-x=x$ . When $x=2018$ , the value of this expression is thus 2018.

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