Question

要过程(x+1)(x-2)=x+1 3x^2-2x-8=0第二个用配方法解

Answer 1

(x+1)(x-2)=x+1

(x+1)(x-3)=0

x=-1或3

3x²-2x-8=0

3x²-2x=8

3x²-2x+1/3=8+1/3

3(x²-2x/3+1/9)=25/3

3(x-1/3)²=25/3

(x-1/3)²=25/9

x-1/3=±5/3

x=1/3±5/3

x=2或-4/3