(2x+3) (2x+5)=? (4x-1)(x-5)

bonsoir

4 x² + 10 x + 6 x + 15 = 4 x² + 16 x + 15

( 4 x - 1) ( x - 5) = 4 x² - 20 x - x + 5 = 4 x² - 21 x + 5

(2x+3)(2x+5)=4x²+16x+15
(4x-1)(x-5)=4x² -21x+5