Question

Answer 1

\(T=\left(m^2-4\right)x^2y^3+5mx^4-7x^2y+10x^4\)

\(=\left(m^2-4\right)x^2y^3+x^4\left(5m+10\right)-7x^2y\)

Để T có bậc là 3 thì \(\left\{{}\begin{matrix}m^2-4=0\\5m+10=0\end{matrix}\right.\)

=>\(\left\{{}\begin{matrix}m^2=4\\5m=-10\end{matrix}\right.\)

=>m=-2