Question

先化简,在求值:a(a+2b)-3(a+b)·(a-b)+(a-b)²,其中a=-1,b=-1/2

今天在发问题20分钟之内必须答出来！不然我就要郁闷 烦了

Answer 1

a(a+2b)-3(a+b)·(a-b)+(a-b)²
=a²+2ab-3(a²-b²)+a² -2ab+b²
=a²+2ab-3a²+3b²+a²-2ab+b²
=-a²+4b²
=-(-1)²+4×（-1/2）²
=-1+1
=0

Answer 2

化简得4b方-a方 答案为0

Answer 3

=a^2+2ab-3a^2+3b^2+a^2-2ab+b^2
=-a^2-2b^2
= -1.5