Respuesta :

The answer is -12...

remember
ab-ac=a(b-c)
we can undistribute the (2m-n) to make it easier
4(2m-n)-3(2m-n)=(2m-n)(4-3)=(2m-n)(1)=(2m-n)

2m-n
for m=-15 and n=-18

2(-15)-(-18)
-30+18
-12