e. To make factoring easier, rearrange the 25 - 20x + 4x2 .
\(\frac{6x^2-11x-10}{6x^2-5x-6}\cdot\frac{6-4x}{4x^2-20x+25}\)
Now we need to factor all the numerators and denominators. Start by splitting their middle terms.
= \(\frac{6x^2+4x-15x-10}{6x^2-9x+4x-6}\cdot\frac{6-4x}{4x^2-10x-10x+25}\)
Now factor by grouping.
= \(\frac{2x(3x+2)-5(3x+2)}{3x(2x-3)+2(2x-3)}\cdot\frac{6-4x}{2x(2x-5)-5(2x-5)}\)
= \(\frac{(3x+2)(2x-5)}{(2x-3)(3x+2)}\cdot\frac{-2(2x-3)}{(2x-5)(2x-5)}\)
Multiply the fractions together.
= \(\frac{(3x+2)(2x-5)(-2)(2x-3)}{(2x-3)(3x+2)(2x-5)(2x-5)}\)
Cancel the common terms.
= \(\frac{{\color{red}(3x+2)}{\color{red}(2x-5)}(-2){\color{red}(2x-3)}}{{\color{red}(2x-3)(3x+2)(2x-5)}(2x-5)}\)
= \(\frac{(-2)}{(2x-5)}\)
= - \(\frac{2}{2x-5}\)
And x ≠ 3/2 or -2/3 since these cause a zero in the denominator of the original expression.