1.
25x²-9=0
(5x+3)(5x-3)=0
5x=-3或5x=3
x=-3/5或3/5
2.
(2x+5)²=5(2x+5)
(2x+5)²-5(2x+5)=0
(2x+5)(2x+5-5)=0
2x(2x+5)=0
x=0或2x=-5
x=0或x=-2.5
3.
4(x-3)²-x(x-3)=0
(x-3)[4(x-3)-x]=0
(x-3)(3x-12)=0
(x-3)(x-4)=0
x=3或x=4
4.
3x(x-2)=5x-10
3x(x-2)-5(x-2)=0
(x-2)(3x-5)=0
x=2或3x=5
x=2或x=5/3