Question

½×²-10=8

①先化简,在求值.8m²-2（3m+4m²-10-8,其中m=-1.
②求当a=-½,b=1时,代数式2a²b-[2ab²-2（a²b+2ab²）]的值.

Answer 1

1、少了个括号,应该是8m^2-2(3m+4m^2-10)-8吧?
原式=8m^2 -6m-8m^2 +20-8
=-6m+12
=6+12
=18

2、原式=2ba^2 -[-2ab^2 -2ba^2]
=2ab^2 +4ba^2
=2*(-1/2)+4*(1/4)
=0