If (a-b)=4 and a b=2, then (a²+b²)= ? · ABC26GN0986
Subject: General Aptitude · Chapter: Simplification
If $(a-b)=4$ and $a b=2$, then $\left(a^{2}+b^{2}\right)=$ ?
(a)18
(b)20
(c)25
(d)None of these
Answer
Explanation
$(a-b)=4 \Rightarrow(a-b)^{2}=4^{2}=16 \Rightarrow a^{2}+b^{2}-2 a b=16$ $$\begin{aligned} \Rightarrow a^{2}+b^{2} & =16+2 a b=16+2 \times 2 \\ & =16+4=20 . \end{aligned}$$
Explanation as extracted from the printed page; notation may be imperfect.
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