Simplify by using formula :(5x - 9) (5x + 9) - Vidyadip

Question

Simplify by using formula $:(5x - 9) (5x + 9)$

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Answer

$(5x - 9) (5x + 9)$
$= (5x)^2- (9)^2$
$= 25x^2 - 81$
$($Using identity : $(a + b) (a - b) = a^2 - b^2).$

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