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
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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