Question

Помогите срочноооооо!!!!!

Answer 1

$(frac{y+1}{y-1}-frac{y}{y+1}):frac{3y+1}{y^2+y}=frac{(y+1)^2-y(y-1)}{(y-1)(y+1)}cdotfrac{y(y+1)}{3y+1}=\ =frac{y^2+2y+1-y^2+y}{y-1}cdotfrac{y}{3y+1}=frac{3y+1}{y-1}cdotfrac{y}{3y+1}=frac{y}{3y+1}$

$frac{3}{x-3}-frac{x+15}{x^2-9}-frac{1}{x}=frac{3x(x+3)-x(x+15)-(x^2-9)}{x(x^2-9)}=\ =frac{3x^2+9x-x^2-15x-x^2+9}{x(x-3)(x+3)}=frac{x^2-6x+9}{x(x-3)(x+3)}=\ =frac{(x-3)^2}{x(x-3)(x+3)}=frac{x-3}{x(x+3)}$