belle_130
幼苗
共回答了14个问题采纳率：78.6% 举报
x^2－x－7/4=0
x^2-x+1/4=2
(x-1/2)^2=2
x-1/2=√2或x-1/2=-√2
x=1/2+√2或x=1/2-√2
3x^2+6x－4=0
3x^2+6x+3=7
3(x+1)^2=7
(x+1)^2=7/3
x+1=√21/3或x+1=-√21/3
x=-1+√21/3或x=-1-√21/3
4x^2－6x－3=0
4x^2-6x+9=12
(2x-3)^2=12
2x-3=2√3或2x-3=-2√3
x=(3+2√3)/2或x=(3-2√3)/2
1年前
9
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