2x²-8=0
x²-4=0
x²-2²=0
(x+2)(x-2)=0
x=-2 or x=2
2x²-8=02x²=8x²=4x=2或x=-2又或者2x²-8=02(x²-4)=0x²-4=0x²=4x=2或x=-2
2x^2-8=0 2x^2=8 x^2=4 x=2或-2
