Đáp án:
f) \(\dfrac{1}{{x - 2}}\)
Giải thích các bước giải:
\(\begin{array}{l}
C4:\\
a)\dfrac{{15{x^3} - 20xy + 8{x^2}}}{{5x}} = \dfrac{{15{x^2} - 20y + 8x}}{5}\\
b)\dfrac{{3x + 5 + x - 7}}{{x + 2}} = \dfrac{{4x - 2}}{{x + 2}}\\
c)\dfrac{{2.5.x + 3\left( {4x - 1} \right)}}{{15\left( {x - 2} \right)}} = \dfrac{{22x - 3}}{{15\left( {x - 2} \right)}}\\
d)\dfrac{{2x - 2}}{{x - 2}}\\
e)\dfrac{1}{{x\left( {x + y} \right)}} + \dfrac{1}{{y\left( {x + y} \right)}}\\
= \dfrac{{x + y}}{{xy\left( {x + y} \right)}} = \dfrac{1}{{xy}}\\
f)\dfrac{{4\left( {x - 2} \right) + 2\left( {x + 2} \right) - 5x + 6}}{{\left( {x - 2} \right)\left( {x + 2} \right)}}\\
= \dfrac{{x + 2}}{{\left( {x - 2} \right)\left( {x + 2} \right)}} = \dfrac{1}{{x - 2}}
\end{array}\)
