Помогите

(5 а+3 в) ² - (5 а-3 в) ²

(a-8) (a-7) - (a-9) ²

2 (x+6) ² - (20x+70)

a² + (3a-2) ²

(5a+7 в) ²-70 ав

(5+у) ²+у (у-7)

(5a+3b) ² - (5a-3b) ² = (25a²+30ab+9b²) - (25a²-30ab+9b²) =

=25a²+30ab+9b²-25a²+30ab-9b²=60ab

(a-8) (a-7) - (a-9) ² = (a²-7a-8a+56) - (a²-18a+81) = a²-15a+56-a²+18a-81=3a-25

2 (x+6) ² - (20x+70) = 2 (x²+12x+36) - 20x-70=2x²+24x+72-20x-70=2x²+4x+2

a² + (3a-2) ²=a²+9a²-12a+4=10a²-12a+4

(5a+7b) ²-70ab=25a²+70ab+49b²-70ab=25a²+49b²

(5+y) ²+y (y-7) = 25+10y+y²+y²-7y=25+3y+2y²