1) x^2 4x/x^2+7x : 24-6x/49-x^2 2) y^3-16y/2y+18 : 4-y/y^2+9y 3) (a+b)^2-2ab/4a^2 :...

Решите задачу:

$1)\frac{ x(x-4)}{ x(x+7)} * \frac{(7-x)(7+x)}{-6(x-4)} = \frac{x-7}{6} ; \\ 2)- \frac{y(4-y)(4+y)}{2(y+9)} * \frac{y(y+9)}{4-y} =- \frac{ y^{2}}{2}(4+y); \\ 3) \frac{ a^{2}+2ab+b^{2}-2ab}{4a^{2} } * \frac{ab}{ a^{2}+ b^{2}} \frac{ab}{4 a^{2} } = \frac{b}{4a}; \\ \\ 4) \frac{5( c-1 ) (c^{2} +c+1)}{c+2} * \frac{13(c+2)}{ c^{2}+2c+1-c} =65(c-1).$