Question

if 5x-2y=7and xy=2 find the value of 25xsquare-4y square

Answer 1

$= 25 {x}^{2} - 4 {y}^{2} \\ = (5x - 2y)(5x + 2y) \\ = 7(7 + 2y + 2y) \\ = 7(7 + 4y) \\ = 49 + 28y$