来自樊瑜瑾的问题
已知:4x^2+5x-1=0,求代数式(2+1)^2-x(x-1)+(x+2)(x-2)的值
已知:4x^2+5x-1=0,求代数式(2+1)^2-x(x-1)+(x+2)(x-2)的值
1回答
2020-05-15 01:08
已知:4x^2+5x-1=0,求代数式(2+1)^2-x(x-1)+(x+2)(x-2)的值
已知:4x^2+5x-1=0,求代数式(2+1)^2-x(x-1)+(x+2)(x-2)的值
4x^2+5x-1=0
4x^2+5x=1
(2+1)^2-x(x-1)+(x+2)(x-2)
=4x^2+4x+1-x^2+x+x^2-4
=4x^2+5x-3
=1-3
=-2