287 × 287+269 × 269-2 × 287 × 269= ? · ABC26GN0180
Subject: General Aptitude · Chapter: Number System
$287 \times 287+269 \times 269-2 \times 287 \times 269=$ ?
(a)534
(b)446
(c)354
(d)324
(e)None of these
Answer
Explanation
$$\begin{aligned} (287 \times 287+269 \times 269- & 2 \times 287 \times 269) \\ & =(287)^{2}+(269)^{2}-(2 \times 287 \times 269) \\ & =(287-269)^{2}=(18)^{2}=324 . \\ & {\left[\because a^{2}+b^{2}-2 a b=(a-b)^{2}\right] } \end{aligned}$$
Explanation as extracted from the printed page; notation may be imperfect.
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