Хелп... -5x(x-2)+(x-3)(5x+1) (5x²y-4xy²)(x-y) (c-7)(c+2) (a²-3)(a²+5) и на фото еще

1) = $- 5 x^{2} +10x+5 x^{2} +x-15x-3= - 4x-3$
2) = $5 x^{3} y-5 x^{2} y^{2} -4 x^{2} y^{2} +4x y^{3} =5 x^{3} y-9 x^{2} y^{2} +4x y^{3}$
3) = $c^{2} +2c-7c-14=c^{2} -5c-14$
4) $a^{4} +5 a^{2} -3 a^{2} -15=a^{4}+2 a^{2} -15$

$\frac{x-y}{-2 (x-y)}= - \frac{1}{2}$
$\frac{(a-3b)^2}{3b-a}= \frac{(3b-a)^2}{3b-ay}=3b-a$

Хелп... -5x(x-2)+(x-3)(5x+1) (5x²y-4xy²)(x-y) (c-7)(c+2) (a²-3)(a²+5) и ** фото еще