Помогите пожалуйста #514 и 515

1) $\frac{ax-y}{a+b} + \frac{y+bx}{a+b} = \frac{ax-y+y+bx}{a+b} = \frac{ax+bx}{a+b} = \frac{x(a+b)}{(a+b)} =x$
2) $\frac{n+mx}{m+3} - \frac{n-3x}{m+3} = \frac{n+mx-n+3x}{m+3} = \frac{mx+3x}{m+3}= \frac{x(m+3)}{(m+3)} = x$
3) $\frac{px-3q}{x-y} + \frac{py-3q}{y-x} = \frac{px-3q}{x-y} - \frac{py-3q}{x-y} = \frac{px-3q-py+3q}{x-y} = \frac{p(x-y)}{(x-y)} = 9$
4) $\frac{2cx+b}{2c-3} + \frac{3x+b}{3-2c} = \frac{2cx+b}{2c-3} - \frac{3x+b}{2c-3} = \frac{2cx+b-3x-b}{2c-3} = \frac{2cx-3x}{2c-3} = \frac{x(2c-3)}{(2c-3)} = x$