不化解的话直接带进去最简单可问题说了要化简啊，帮帮忙吧化解=2a-(3a-6b)[1-(10a-5b)] =2a-(3a-6b)[1-10a+5b] =2a-(3a-30a^2+15ab-6b+60ab-30b^2) =2a-(3a-30a^2+75ab-6b-30b^2) =-a+30a^2-75ab+6b+30b^2将a=1,b=-5代入式中得原式=-1+30+75x5-6x5+30x25=1124