Question

ПРОШУ ПОМОГИТЕ ОЧЕНЬ НАДО! ДАМ 35 БАЛЛОВ

Answer 1

$1.\;\frac{y+c}c\cdot\left(\frac cy+\frac c{y+c}\right)=\frac{y+c}c\cdot\frac cy+\frac{y+c}c\cdot\frac c{y+c}=\frac{y+c}y+1=\frac{y+c+y}y=\frac{2y+c};\\\\\\2.\;\left(\frac{c-d}{c^2+cd}-\frac c{d^2+cd}\right):\left(\frac{d^2}{c^3-cd^2}+\frac1{c+d}\right)=\left(\frac{c-d}{c(c+d)}-\frac c{d(c+d)}}\right):\left(\frac{d^2}{c(c^2-d^2)}+\frac1{c+d}\right)=$

$=\frac{cd-d^2-c^2}{cd(c+d)}:\left(\frac{d^2}{c(c-d)(c+d)}+\frac1{c+d}\right)=\frac{cd-d^2-c^2}{cd(c+d)}:\frac{d^2+c^2-cd}{c(c-d)(c+d)}=\\\\=\frac{cd-d^2-c^2}{cd(c+d)}\cdot\frac{c(c-d)(c+d)}{d^2+c^2-cd}=\frac{-(d^2+c^2-cd)}d\cdot\frac{c-d}{d^2+c^2-cd}=-\frac{c-d}d=\frac{d-c}d$