Đáp án:
\(\begin{array}{l}
a)2a - 6\\
b){b^2} - b\\
c)3y\\
d)\dfrac{4}{x}\\
e)\dfrac{{\sqrt x - 1}}{{\sqrt x + 1}}
\end{array}\)
Giải thích các bước giải:
\(\begin{array}{l}
a)2.\left| {a - 3} \right| = 2\left( {a - 3} \right) = 2a - 6\\
b)\left| {b\left( {b - 1} \right)} \right| = - b.\left( { - b + 1} \right)\\
= {b^2} - b\\
c)\dfrac{{3\sqrt 7 }}{{\sqrt 7 }}.\left| y \right| = 3y\\
d)\dfrac{{4\sqrt 3 }}{{\sqrt 3 }}.\dfrac{1}{{\sqrt {{x^2}} }} = \dfrac{4}{{\left| x \right|}} = \dfrac{4}{x}\\
e)\sqrt {\dfrac{{{{\left( {\sqrt x - 1} \right)}^2}}}{{{{\left( {\sqrt x + 1} \right)}^2}}}} = \dfrac{{\left| {\sqrt x - 1} \right|}}{{\left| {\sqrt x + 1} \right|}} = \dfrac{{\sqrt x - 1}}{{\sqrt x + 1}}
\end{array}\)
