(5а+3в)(3в-5а). Упростите

Question

(5а+3в)(3в-5а). Упростите

Answer 1

15ab-25a2+9b2-25ab=-25a2-10ab+9b2

Answer 2

(5a+3b)(3b-5a)=(3b+5a)(3b-5a)=9b²-25a²

(x²-y²=(x+y)(x-y))

(5a+3b)(3b-5a)=5a.3b - 5a.5a + 3b.3b - 3b.5a=15ab-25a²+9b²-15a²=
=9b²-25a²