Question

急 已知-3x的m-2n次方×y的-n+2次方与5分之1x的3次方×y的-4+m次方是同类项,

Answer 1

m-2n=3

-n+2=-4+m

∴m-2n=3

m+n=6

∴（m-2n）的2次方-5（m+n）-2（m-2n）的2次方+m+n

=-(m-2n)²-4(m+n)

=-9-24

=-33