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Identities — MATHS STD 8 — Question

ICSE BoardEnglish MediumSTD 8MATHSIdentities4 Marks
Question
If $a^2 + b^2 = 29$ and $ab = 10$, find $: a + b$
✓

Answer

$(a+b)^2=a^2+b^2+2 a b$
$\Rightarrow(a+b)^2=29+2 \times 10$
$\Rightarrow(a+b)^2=29+20$
$\Rightarrow(a+b)^2=49$
$\Rightarrow a+b=\sqrt{49}$
$\Rightarrow \mathrm{a}+\mathrm{b}= \pm 7$

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