a)
\frac{3}{5x} = \frac{3x^2}{}
zał. x\ne0
\frac{3}{5x} = \frac{3x^2}{5x*x^2}
\frac{3}{5x} = \frac{3x^2}{5x^3}
b)
\frac{-2x^2}{5} = \frac{8x^5}{}
\frac{-2x^2}{5} = \frac{8x^5}{5*(-4x^3)}
zał. x\ne0
\frac{-2x^2}{5} = \frac{8x^5}{-20x^3}
c)
\frac{9-x}{3} = \frac{81-x^2}{}
\frac{9-x}{3} = \frac{81-x^2}{3(9+x)}
zał. x\ne-9
\frac{9-x}{3} = \frac{81-x^2}{27+3x}
d)
\frac{5}{x+2}= \frac{5x-10}{}
\frac{5}{x+2}= \frac{5x-10}{(x+2)(x-2)} |wzór skróconego mnożenia (a-b)(a+b)=a^2-b^2
zał. x\ne0
\frac{5}{x+2}= \frac{5x-10}{x^2-4}
e)
\frac{3x-1}{x^2+5}= \frac{3x^3-x^2}{}
\frac{3x-1}{x^2+5}= \frac{3x^3-x^2}{x^2(x^2+5)}
zał. x\ne0
\frac{3x-1}{x^2+5}= \frac{3x^3-x^2}{x^4+5x^2}
f)
\frac{x^2-3}{x} = \frac{x^4-9}{}
\frac{x^2-3}{x} = \frac{x^4-9}{x(x+3)}
zał. x\ne0 , x\ne -3
\frac{x^2-3}{x} = \frac{x^4-9}{x^2+3x}