X2-X+1/4=0 x2+8x+15=0 2x2+5x+2=0 x2-5=4x 用配方法 2(x-3)2=x2-9用分解因式法

问题描述:

X2-X+1/4=0 x2+8x+15=0 2x2+5x+2=0 x2-5=4x 用配方法 2(x-3)2=x2-9用分解因式法

X²-X+1/4=0(x-1/2)²=0x=1/2x²+8x+15=0x²+8x+16=1(x+4)²=1x+4=±1x=-3,或x=-52x²+5x+2=0(2x+1)(x+2)=0x=-1/2,或x=-2x²-5=4x x²-4x+4=9(x-2)²=3²x-2=±3...