已知|a 1|与(2a-b)2互为相反数已知|a+1|与(2a-b)2互为相反数,求3ab-15b2+5a2-6ab+15a2-2b2的值.

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已知|a 1|与(2a-b)2互为相反数已知|a+1|与(2a-b)2互为相反数,求3ab-15b2+5a2-6ab+15a2-2b2的值.

已知|a 1|与(2a-b)2互为相反数已知|a+1|与(2a-b)2互为相反数,求3ab-15b2+5a2-6ab+15a2-2b2的值.
已知|a 1|与(2a-b)2互为相反数
已知|a+1|与(2a-b)2互为相反数,求3ab-15b2+5a2-6ab+15a2-2b2的值.

已知|a 1|与(2a-b)2互为相反数已知|a+1|与(2a-b)2互为相反数,求3ab-15b2+5a2-6ab+15a2-2b2的值.

|a+1| 与 (2a-b)^2 互为相反数,所以 |a+1| +(2a-b)^2 =0
可得 a+1 =0,2a-b =0
即 a = -1,b = -2
3ab-15b^2+5a^2-6ab+15a^2-2b^2
= 20a^2 -3ab -17b^2
= (20a+17b)(a-b)
= (-20-34)(-1+2)
= -54×1
= - 54
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则a 1=2a-b=0;
a=-1;b=-2;
原式=20a²-17b²-3ab
=20-17×4-3×(-1)×(-2)
=20-68-6
=-54;