Question

解下列方程：1、（x-3)=x(x-3) 2、5x的2次=4x3、（x-2)的2次=（2x+3)的2次4、x的3次-16

Answer 1

1.

(x-3)=x(x-3)

(x-3)-x(x-3)=0

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

x=3或x=1

2.

5x^2=4x

5x^2-4x=0

x(5x-4)=0

x=0或x=4/5

3.

(x-2)^2=(2x+3)^2

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

(x-2+2x+3)(x-2-2x-3)=0

(3x+1)(-x-5)=0

3x=1或x+5=0

x=-1/3或x=-5

4.

x^3-16x=0

x(x^2-16)=0

x(x+4)(x-4)=0

x=0或x=-4或x=4