已知/a+3/+[2a-b]^2=0,求多项式0.5ab-3a^2+7b^2-2ab+3a^2-8b^2的值

来源:学生作业帮助网 编辑:作业帮 时间:2024/10/02 11:42:22
已知/a+3/+[2a-b]^2=0,求多项式0.5ab-3a^2+7b^2-2ab+3a^2-8b^2的值
xSN@*OHUK3PE"EiPvM, "dçf/L8(}Il{999i3+.ϧ"(|51/suu0<,F=|S"tpmBhR=T'~|2arЛ|:| &HVD8MCF9:0]Tiԯy sZa-̮Xl+Ӽ59W<} *MkJlJ-Y`d9[]%@z{dJL挗gioo?nWمՀtKaV0>)~ b~8ۿܿqf j)PuCQ Xp{ߗD4$4}W&Z'qS.랇3zuӃK^[ @h k%Ydp.n/H4t.&@JjDe1ȨbbBMAj &٫

已知/a+3/+[2a-b]^2=0,求多项式0.5ab-3a^2+7b^2-2ab+3a^2-8b^2的值
已知/a+3/+[2a-b]^2=0,求多项式0.5ab-3a^2+7b^2-2ab+3a^2-8b^2的值

已知/a+3/+[2a-b]^2=0,求多项式0.5ab-3a^2+7b^2-2ab+3a^2-8b^2的值
依题意有:/a+3/=0,得a=-3
2a-b=0,得b=-6
原式=-1.5ab-b^2
=-1.5*(-3)(-6)-(-6)^2
=-63

|a+3|+(2a-b)²=0
则:a+3=0且2a-b=0
得:a=-3、b=-6
则:0.5ab-3a²+7b²-2ab+3a²-8b²
=-b²-1.5ab
=-(6²)-1.5×(-3)×(-6)
=-36-27
=-63

a+3=0,a=-3;
2a-b=0,b=2a=-6;
0.5ab-3a^2+7b^2-2ab+3a^2-8b^2=-b^2-1.5ab=-36-1.5*18=-63

绝对值和平方都>=0
只能
|a+3|=0 a=-3
[2a-b]^2=0 2a-b=0 b=6
0.5ab-3a^2+7b^2-2ab+3a^2-8b^2
=0.5ab-2ab+3a^2-3a^2+7b^2-8b^2
=-1.5ab-b^2
=1.5*3*6-36
=27-36
=-9

/a+3/+[2a-b]^2=0
==》a+3=0 2a-b=0
==>a=-3,b=-6
0.5ab-3a^2+7b^2-2ab+3a^2-8b^2
=0.5ab-2ab-3a^2+3a^2+7b^2-8b^2
=-1.5ab-b^2
=-27-36
=-63

(2a-3b)(3a-2b)+(2a-b)^2+(2ab^2)^3÷8/3*a^3*b^4 =6a -=10a -17ab+10b =10*6-17*(-3) =60+51 =111