已知整式-5x²+ax+bx²+2x+5的值与x的取值无关,求2a²+3ab+b²-6ab+9的值
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已知整式-5x²+ax+bx²+2x+5的值与x的取值无关,求2a²+3ab+b²-6ab+9的值
已知整式-5x²+ax+bx²+2x+5的值与x的取值无关,求2a²+3ab+b²-6ab+9的值
已知整式-5x²+ax+bx²+2x+5的值与x的取值无关,求2a²+3ab+b²-6ab+9的值
-5x²+ax+bx²+2x+5
=(b-5)x²+(a+2)x+5
∵该整式的值与x的取值无关
∴b-5=0,a+2=0
∴b=5,a=-2
∴2a²+3ab+b²-6ab+9
=2a²-3ab+b²+9
=2×4-3×(-2)×5+25+9
=8+30+25+9
=72