1.a)\(2a^2b\left(x+y\right)-4a^3b\left(-x-y\right)\)
\(=2a^2b\left(x+y\right)+4a^3b\left(x+y\right)\)
\(=2a^2b\left(1+2a\right)\left(x+y\right)\)
b)\(x^{m+1}+x^m\)
\(=x^m.x+x^m\)
\(=x^m\left(x+1\right)\)
c)\(x^{m+2}-x^{m+1}\)
\(=x^{m+1}.x-x^{m+1}\)
\(=x^{m+1}\left(x-1\right)\)