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Algebraic Expressions, Identities and Factorisation — MATHS STD 8 — Question

Gujarat BoardEnglish MediumSTD 8MATHSAlgebraic Expressions, Identities and Factorisation2 Marks
Question
If $m - n = 16$ and $m^2+ n^2= 400$, then find $mn$.
✓

Answer

Given, $m - n = 16$ and $m^2+ n^2= 400$
Since,
$ (m-n)^2=m^2+n^2-2 m n $
$ (16)^2=400-2 m n $
$ 2 m n=400-(16)^2 $
$2mn = 400 - 256$
$\text{mn}=\frac{144}{2}$
$= 72$

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