8x²-16=0求解 x²=2x=±√2（x+2）²-3=0求解(x+2)²=3x+2=±√3x=-2±√3x²+4x-3=0求解 x²＋4x+4=7(x+2)²=7x+2=±√7x=-2±√73x²-8x+2=0求解3(x²-8/3x)=23(x-4/3)²...