Question

помогите пж кто-нибудь.8 класс ​

Answer 1

Объяснение:

$1)\ \frac{x}{x-y} +\frac{y}{y-x} = \frac{x}{x-y} -\frac{y}{x-y}=\frac{x-y}{x-y} =1.\\2)\ \frac{2x+1}{a} +\frac{3x+1}{a}-\frac{x-2}{a}=\frac{2x+1+3x+1-(x-2)}{a} =\frac{5x+2-x+2}{a}=\frac{4x+4}{a}=\frac{4*(x+1)}{a} .\\3)\ \frac{a}{12m}-\frac{b}{18n} =\frac{3an-2bm}{36mn}.$

$4)\ \frac{3xy}{4mn} *\frac{10m^2n^2}{21x^2y} =\frac{5mn}{2*7x}=\frac{5mn}{14x}.\\5)\ -\frac{18a^2b^2}{5pq}:\frac{6ab}{5p^2q^2}=-\frac{18a^2b^2}{5pq}*\frac{5p^2q^2}{6ab}=-3abpq. \\6)\ \frac{x^2y-4y^3}{3xy^2}*\frac{yx^2}{x^2-2xy}= \frac{y*(x^2-4y^2)*x}{3*x*(x-2y)*y}=\frac{(x-2y)*(x+2y)}{3*(x-2y)} =\frac{x+2y}{3} .$