Question

3 вариант 1,2,3 задание ​

Answer 1

$1)(\frac{7x-3y}{2x}+\frac{2x-7y}{2y})\cdot\frac{4xy}{2x^2-3y^2}=\frac{y\cdot(7x-3y)+x\cdot(2x-7y)}{2xy}\cdot\frac{4xy}{2x^2-3y^2}=(7xy-3y^2+2x^2-7xy)\cdot\frac{2}{2x^2-3y^2}=(-3y^2+2x^2)\cdot\frac{2}{2x^2-3y^2}=2\\2)(1+\frac{x}{y}):(1-\frac{x}{y})=\frac{y+x}{y}:\frac{y-x}{y}=\frac{y+x}{y}\cdot\frac{y}{y-x}=(y+x)\cdot\frac{1}{y-x}=\frac{y+x}{y-x}$

$3) \frac{15c}{5-c}+\frac{6c}{c^2-25}\cdot\frac{7c+35}{3}=\frac{15c}{-(c-5)}+\frac{2c}{(c-5)\cdot(c+5)}\cdot7(c+5)=-\frac{15c}{c-5}+\frac{2c}{c-5}\cdot7=\frac{-15c}{c-5}+\frac{14c}{c-5}=\frac{c}{c-5}$