8a^3 (4a^2- b^2)/(2a+b) (4a^2 -4ab=b^2) help me 09/08/2021 Bởi Aubrey 8a^3 (4a^2- b^2)/(2a+b) (4a^2 -4ab=b^2) help me
Đáp án: \[\frac{{8{a^3}}}{{2a – b}}\] Giải thích các bước giải: Ta có: \(\begin{array}{l}\frac{{8{a^3}\left( {4{a^2} – {b^2}} \right)}}{{\left( {2a + b} \right)\left( {4{a^2} – 4ab + {b^2}} \right)}}\\ = \frac{{8{a^3}\left[ {{{\left( {2a} \right)}^2} – {b^2}} \right]}}{{\left( {2a + b} \right)\left[ {{{\left( {2a} \right)}^2} – 2.2a.b + {b^2}} \right]}}\\ = \frac{{8{a^3}\left( {2a – b} \right)\left( {2a + b} \right)}}{{\left( {2a + b} \right){{\left( {2a – b} \right)}^2}}} = \frac{{8{a^3}}}{{2a – b}}\end{array}\) Bình luận
Đáp án:
\[\frac{{8{a^3}}}{{2a – b}}\]
Giải thích các bước giải:
Ta có:
\(\begin{array}{l}
\frac{{8{a^3}\left( {4{a^2} – {b^2}} \right)}}{{\left( {2a + b} \right)\left( {4{a^2} – 4ab + {b^2}} \right)}}\\
= \frac{{8{a^3}\left[ {{{\left( {2a} \right)}^2} – {b^2}} \right]}}{{\left( {2a + b} \right)\left[ {{{\left( {2a} \right)}^2} – 2.2a.b + {b^2}} \right]}}\\
= \frac{{8{a^3}\left( {2a – b} \right)\left( {2a + b} \right)}}{{\left( {2a + b} \right){{\left( {2a – b} \right)}^2}}} = \frac{{8{a^3}}}{{2a – b}}
\end{array}\)