Question

(5a + 7)² - 4b²
descompuneti in factori

Answer 1

Folosim formula $a^{2} - b^{2} =(a+b)(a-b)$ si vom aveam:
(5a+7-2b)(5a+7+2b)

Answer 2

(5a+7)²-4b²=5a²+2*(5a*7)+7²-4b²=25a²+2*(35a)+49-4b²=
=25a²+70a+49-4b²=a(25a+70)-4b²+49

(5a+7)²-4b²=(5a-2b+7)(5a+2b+7)