Đáp án:
b) \(\dfrac{4}{{x - 1}}\)
Giải thích các bước giải:
\(\begin{array}{l}
a)\dfrac{{4{x^2} - 12x + 8}}{{x - 2}} = \dfrac{{4\left( {{x^2} - 3x + 2} \right)}}{{x - 2}}\\
= \dfrac{{4\left( {{x^2} - x - 2x + 2} \right)}}{{x - 2}} = \dfrac{{4\left[ {x\left( {x - 1} \right) - 2\left( {x - 1} \right)} \right]}}{{x - 2}}\\
= \dfrac{{4\left( {x - 1} \right)\left( {x - 2} \right)}}{{x - 2}} = 4\left( {x - 1} \right)\\
b)\dfrac{{{{\left( {x + 1} \right)}^2} - {{\left( {x - 1} \right)}^2} + 4}}{{\left( {x - 1} \right)\left( {x + 1} \right)}}\\
= \dfrac{{{x^2} + 2x + 1 - {x^2} + 2x - 1 + 4}}{{\left( {x - 1} \right)\left( {x + 1} \right)}}\\
= \dfrac{{4x + 4}}{{\left( {x - 1} \right)\left( {x + 1} \right)}} = \dfrac{4}{{x - 1}}\\
c)5{x^4} + 35{x^3} + 2{x^2} + 14x
\end{array}\)
