ПОМОГИТЕ! СРОЧНО!!!!!! СПАСИТЕ!!!!!!!!!!!!!!!!!!

1)
$a) \frac{14a^3b^5}{21a^4b}= \frac{2b^4}{3a} \\ \\ b) \frac{x^2+x}{x^2}= \frac{x(x+1)}{x^2}= \frac{x+1}{x} \\ \\ c) \frac{a+2b}{a^2-4b^2}= \frac{a+2b}{(a-2b)(a+2b)}= \frac{1}{a-2b}$

2)
$a) \frac{2x}{x-a}- \frac{2a}{x+a}= \frac{2x(x+a)-2a(x-a)}{(x-a)(x+a)}= \frac{2x^2+2ax-2ax+2a^2}{x^2-a^2}= \frac{2x^2+2a^2}{x^2-a^2} \\ \\ b) \frac{2-ab}{2a+ab} + \frac{2b}{2+b}= \frac{2-ab}{a(2+b)}+ \frac{2b}{2+b}= \frac{2-ab+2ab}{a(2+b)}= \frac{2+ab}{2a+ab} \\ \\ c)c- \frac{c^2}{c+1}= \frac{c(c+1)-c^2}{c+1}= \frac{c^2+c-c^2}{c+1}= \frac{c}{c+1}$

3)
$\frac{7}{(x-y)(x+y)}- \frac{5}{x(y-x)} - \frac{12}{x(x+y)} =- \frac{7}{(y-x)(x+y)}- \frac{5}{x(y-x)} - \frac{12}{x(x+y)}= \\ \\ = - \frac{7x+5(x+y)+12(y-x)}{x(y-x)(x+y)}= -\frac{7x+5x+5y+12y-12x}{x(y-x)(y+x)} = -\frac{17y}{x(y^2-x^2)}= -\frac{17y}{xy^2-x^3}$

4)
$\frac{ax-ay+3x-3y}{a^2-9}= \frac{a(x-y)+3(x-y)}{(a-3)(a+3)}= \frac{(a+3)(x-y)}{(a-3)(a+3)}= \frac{x-y}{a-3} = \frac{5.8-3.4}{3.1-3}= \frac{2.4}{0.1}=24$