(1/2)若多项式4x^2+axy-y^2与2bx^2-3xy+y^2的差的值与字母x无关,求代数式2(a^2-ab+b^2)-3(b^2-a^
问题描述:
(1/2)若多项式4x^2+axy-y^2与2bx^2-3xy+y^2的差的值与字母x无关,求代数式2(a^2-ab+b^2)-3(b^2-a^
答
4x²+axy-y²-(2bx²-3xy+y²)=4x²+axy-y²-2bx²+3xy-y²=x²(4-2b)+xy(a+3)其值与x无关,则有4-2b=0a+3=0故a=-3 b=2,把a、b的值代入2(a²-ab+b²)-3(b²-a...