Question
Evaluate : $(5x + 8y) (3x + 5y)$

Answer

$ (5x + 8y) (3x + 5y)$
$= 5x (3x + 5y) + 8y (3x+ 5y)$
$= 15x^2 + 25xy + 24xy + 40y^2$
$= 15x^2 + 49xy + 40y^2$

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