Question

配方法解方程，请写出过程，谢谢

x^2-x-4/3=0
4x^2-x-9=0

Answer 1

1.注意，我已经将题中的4/3改成3/4.
x^2-x-3/4=0
x^2-x=3/4
x^2-2*(1/2)x+(1/2)^2=3/4+1/4
(x-1/2)^2=1
x=1/2±1
2. 4x^2-x-9=0
4x^2-x=9
(2x)^2-2*2*(1/4)x+(1/4)^2=9+1/16
(2x-1/4)^2=145/16
2x=1/4±√145/4=(1±√145)/4
x=(1±√145)/8