If a2 + b2 = 10 and a2 -b2 =8, what is the value of ab?

root 2

none of these

প্রশ্ন: If a2 + b2 = 10 and a2 -b2 =8, what is the value of ab?

ব্যাখ্যা:

$a^{2} + b^{2} = 10; a^{2} - b^{2} = 8$
$∴$ $2 a^{2}$ = 18; $a^{2}$ = 9 $\Rightarrow$ a = 3
2 $b^{2}$ = 2;b = 1
$∴$ ab = $3 \times 1$ = 3

One Bank Ltd One Bank Ltd - Special Cadre Officer - 09.11.2012 গণিত

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