Question

Answer 1

1:

a: \(\dfrac{5y}{7}=\dfrac{5y\cdot4x}{7\cdot4x}=\dfrac{20xy}{28x}\)

b: \(\dfrac{3x\left(x+5\right)}{2\left(x+5\right)}=\dfrac{3x\left(x+5\right):\left(x+5\right)}{2\left(x+5\right):\left(x+5\right)}=\dfrac{3x}{2}\)

c: \(\dfrac{x+2}{x-1}=\dfrac{\left(x+2\right)\left(x+1\right)}{\left(x-1\right)\left(x+1\right)}=\dfrac{\left(x+2\right)\left(x+1\right)}{x^2-1}\)

d: \(\dfrac{x^2-x-2}{x+1}=\dfrac{\left(x-2\right)\left(x+1\right)}{x+1}=\dfrac{x-2}{1}\)

\(=\dfrac{\left(x-2\right)\left(x-1\right)}{x-1}=\dfrac{x^2-3x+2}{x-1}\)

e: \(\dfrac{x^3+8}{x^2-2x+4}=\dfrac{\left(x+2\right)\left(x^2-2x+2^2\right)}{x^2-2x+2^2}=x+2\)