Competition problem — Algebra — Maths Olympiad Prep

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Algebra Difficulty 1.8 Junior Find the answer

When $x=3$ and $y=4$ , what is the value of the expression $xy-x$ ?

Your answer

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

Solution

When $x=3$ and $y=4$ , we get $xy-x=3 \times 4-3=12-3=9$ . Alternatively, $xy-x=x(y-1)=3 \times 3=9$ .

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