解方程 2(x-3)=x平方-9

问题描述:

解方程 2(x-3)=x平方-9

x=-1或x=3

2(x-3)=x^2-9
x^2-2x+6-9=0
x^2-2x-3=0
(x-3)(x+1)=0
x=3或 x=-1

2(x-3)=x²-9
解:2(x-3)=(x-3)(x+3)
2=x+3
x=-1

2(x-3)=(x+3)(x-3),x=-1.

2(x-3)=x^2-9
2(x-3)-(x-3)(x+3)=0
(x-3)(2-x-3)=0
(x-3)(-x-1)=0
(x-3)(x+1)=0

x=3 或 x=-1

2(x-3)=x平方-9
2(x-3)=(x-3)(x+3)
2(x-3)-(x-3)(x+3)=0
(x-3)(2-x-3)=0
(x-3)(-x-1)=0
x1=3 x2=-1

2﹙x-3﹚-﹙x-3﹚﹙x+3﹚=0
﹙x-3﹚﹙2-x-3﹚=0
﹙x-3﹚﹙x+1﹚=0
x1=3
x2=﹣1.