(x+1)的平方等于3,求x等于几

2025-12-15 00:48:22
推荐回答(3个)
回答1:

两边同时开平方,x+1等于±根号下3,x等于正负根号下3减1

回答2:

x²+x²/(x+1)²=3
设t=x+1
x=t-1

(t-1)²+(t-1)²/t²=3
t²-2t+1+1-2/t+1/t²=3
t²+2+1/t²-2t-2/t²=3
(t+1/t)²-2(t-1/t)=3

令y=t+1/t
y²-2y-3=0
(y-3)(y+1)=0
y=3 y=-1

x+1+1/(x+1)=3
(x+1)²+1=3x+3
x²+2x+2=3x+3
x²-x-1=0
(x-1/2)²-5/4=0
x-1/2=±√5/2
x=1/2±√5/2

x+1+1/(x+1)=-1
(x+1)²+1=-x-1
x²+2x+2=-x-1
x²+3x+3=0
无解

所以 x=1/2±√5/2

回答3:

±根号3减1