Ta có :
\(\left\{{}\begin{matrix}a^3+3ab^2=63\\b^3+3a^2b=62\end{matrix}\right.\Rightarrow a^3+3a^2b+3ab^2+b^3=125\Rightarrow\left(a+b\right)^3=125\Rightarrow a+b=5\)
\(\left\{{}\begin{matrix}a^3+3ab^2=63\\b^3+3a^2b=62\end{matrix}\right.\Rightarrow a^3-3a^2b+3ab^2-b^3=1\Rightarrow\left(a-b\right)^3=1\Rightarrow a-b=1\)
\(\Rightarrow M=a^2-b^2=\left(a+b\right)\left(a-b\right)=5.1=5\)
Vậy \(M=5\)
Học tốt !
\(a^3+3ab^2+b^3+3a^2b=63+62=125=\left(a+b\right)^3\)
\(\Rightarrow a+b=5\)
\(a^3+3ab^2-b^3-3a^2b=63-62=1=\left(a-b\right)^3\)
\(\Rightarrow a-b=1\)
\(a^2-b^2=\left(a+b\right)\left(a-b\right)\)
Mà \(a+b=5;a-b=1\)
\(\Rightarrow a^2-b^2=5.1=5\)
Vậy ...
