Question

помогите пожалуйста люди добрые ​

Answer 1

$1)\frac{y-20}{4y}+\frac{5y-2}{y^{2}}=\frac{y(y-20)+4(5y-2)}{4y^{2}}=\frac{y^{2}-20y+20y-8 }{4y^{2}}=\frac{y^{2}-8}{4y^{2}} \\\\2)\frac{14b^{2}-c }{7b} -2b=\frac{14b^{2}-c-2b*7b }{7b}=\frac{14b^{2}-c-14b^{2}}{7b}=-\frac{c}{7b}\\\\b=0,5;c=-14\\\\-\frac{c}{7b}=-\frac{-14}{7*0,5}=\frac{14}{3,5}=4$

$3)\frac{16x^{4}y^{6}}{64x^{3}y^{7}} =\frac{1}{4} x^{4-3}y^{6-7}=\frac{1}{4}xy^{-1}= \frac{x}{4y} \\\\4)\frac{3m}{m^{2}-7m }=\frac{3m}{m(m-7)}=\frac{3}{m-7}$