X^2-2X-3=0 X^2-2X=2 2X^2-7X=-8 X^2+3=3(X+1) (X-1)(X+3)=12

问题描述:

X^2-2X-3=0 X^2-2X=2 2X^2-7X=-8 X^2+3=3(X+1) (X-1)(X+3)=12

X^2-2X-3=0
(x-3)(x+1)=0
x1=3x2=-1
X^2-2X=2
X^2-2X+1=3
(x-1)^2=3
x-1=±√3
x=1±√3
2X^2-7X=-8
x^2-7/2x=-4
x^2-7/2x+(7/4)^2=(7/4)^2-4
(x-7/4)^2=49/16-4
(x-7/4)^2=-15/16
所以无解
X^2+3=3(X+1)
x^2+3=3x+3
x^2-3x=0
x(x-3)=0
x1=0x2=3
(X-1)(X+3)=12
x^2+2x-3=12
x^2+2x-15=0
(x+5)(x-3)=0
x1=-5x2=3
请好评
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