先化简再求值(3m+1)(2m-3)-(6m-5)(m-4),其中m=负1/2

问题描述:

先化简再求值(3m+1)(2m-3)-(6m-5)(m-4),其中m=负1/2

原式=6m²-7m-3-6m²+29m-20
=22m-23
当m=﹣1/2时,
原式=22×﹙﹣1/2﹚-23=﹣34.