若多项式3x²+axy-2y²+1与2bx²-3xy+y²的差值与x的取值无关,求代数式2(a²-2ab+b²)-3(b²-a²)的值?
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![若多项式3x²+axy-2y²+1与2bx²-3xy+y²的差值与x的取值无关,求代数式2(a²-2ab+b²)-3(b²-a²)的值?](/uploads/image/z/5934326-14-6.jpg?t=%E8%8B%A5%E5%A4%9A%E9%A1%B9%E5%BC%8F3x%26%23178%3B%2Baxy-2y%26%23178%3B%2B1%E4%B8%8E2bx%26%23178%3B-3xy%2By%26%23178%3B%E7%9A%84%E5%B7%AE%E5%80%BC%E4%B8%8Ex%E7%9A%84%E5%8F%96%E5%80%BC%E6%97%A0%E5%85%B3%2C%E6%B1%82%E4%BB%A3%E6%95%B0%E5%BC%8F2%EF%BC%88a%26%23178%3B-2ab%2Bb%26%23178%3B%EF%BC%89-3%EF%BC%88b%26%23178%3B-a%26%23178%3B%EF%BC%89%E7%9A%84%E5%80%BC%3F)
若多项式3x²+axy-2y²+1与2bx²-3xy+y²的差值与x的取值无关,求代数式2(a²-2ab+b²)-3(b²-a²)的值?
若多项式3x²+axy-2y²+1与2bx²-3xy+y²的差值与x的取值无关,
求代数式2(a²-2ab+b²)-3(b²-a²)的值?
若多项式3x²+axy-2y²+1与2bx²-3xy+y²的差值与x的取值无关,求代数式2(a²-2ab+b²)-3(b²-a²)的值?
差=3x²+axy-2y²+1-2bx²+3xy-y²
=(3-2b)x²+(a+3)xy-3y²+1
和x无关则含x的项系数为0
3-2b=0,a+3=0
a=-3,b=3/2
所以原式=2a²-4ab+2b²-3b²+3a²
=5a²-4ab-b²
=45+18-9/4
=243/4