Question

Решите пожалуйста.Срочно!!!

Answer 1

1.
а)$frac{2-b}{b}+ frac{b-3}{3b^2}=frac{3b*(2-b)+b-3}{3b^2}=frac{6b-3b^2+b-3}{3b^2}=frac{7b-3b^2-3}{3b^2}$
б)$frac{3c+9}{6c}*frac{2c^4}{c+3}=frac{3(c+3)*2c^4}{6c*(c+3)}=c^3$
в)$frac{x^2-y^2}{6y}:(x-y)^2=frac{(x-y)*(x+y)}{6y*(x-y)^2}=frac{x+y}{6y*(x-y)}$
2.
$frac{5}{a}-frac{a}{4-a}*frac{16-a^2}{a^2}=frac{5}{a}-frac{a*(4-a)*(4+a)}{(4-a)*a^2}=frac{5}{a}-frac{4+a}{a}=frac{5-4-a}{a}=frac{1-a}{a}$
3.
$frac{x^2+14xy+49y^2}{x^2-49y^2}*(21y-3x):(7x^2+49xy)= \ \ frac{(x+7y)^2*(-3)*(x-7y)}{(x-7y)*(x+7y)*7x*(x+7y)}=-frac{3}{7x} \ \ -frac{3}{7*9}=-frac{3}{63}=-frac{1}{21}$