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Identities — MATHS STD 8 — Question

ICSE BoardEnglish MediumSTD 8MATHSIdentities4 Marks
Question
If $a – b = 6$ and $ab = 16,$ find $a^2 + b^2$
✓

Answer

$(a − b)^2 = a^2+ b^2 − 2ab$
$\Rightarrow (6)^2= a^2 + b^2 − 2\times 16$
$\Rightarrow 36 = a^2 + b^2 − 32$
$\Rightarrow 36 + 32 = a^2 + b^2$
$\Rightarrow 68 = a^2 + b^2$
$\therefore a^2 + b^2 = 68$

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