神马作文网求大神用配方法,
来源：学生作业帮 编辑：神马作文网作业帮 分类：数学作业 时间：2024/11/12 21:38:29
求大神用配方法,
3x^2+6x-4=0
3(x^2+2x+1)-7=0
3(x+1)^2=7
(x+1)^2=7/3
x+1=√21/3或-√21/3
x=√21/3-1或x=-√21/3-1
4x^2-6x-3=0
4(x^2-3/2x+(3/4)^2)-9/4-3=0
4(x-3/4)^2=21/4
(x-3/4)^2=21/16
x-3/4=√21/4或-√21/4
x=√21/4+3/4或x=3/4-√21/4
x^2+4x-9=2x-11
x^2+2x+2=0
(x+1)^2+1=0
故无解
x(x+4)=8x+12
x^2-4x+4=16
(x-2)^2=16
x-2=4或-4
x=6或x=-2
望采纳!谢谢
再问： 谢谢了
再答： 不客气
3(x^2+2x+1)-7=0
3(x+1)^2=7
(x+1)^2=7/3
x+1=√21/3或-√21/3
x=√21/3-1或x=-√21/3-1
4x^2-6x-3=0
4(x^2-3/2x+(3/4)^2)-9/4-3=0
4(x-3/4)^2=21/4
(x-3/4)^2=21/16
x-3/4=√21/4或-√21/4
x=√21/4+3/4或x=3/4-√21/4
x^2+4x-9=2x-11
x^2+2x+2=0
(x+1)^2+1=0
故无解
x(x+4)=8x+12
x^2-4x+4=16
(x-2)^2=16
x-2=4或-4
x=6或x=-2
望采纳!谢谢
再问： 谢谢了
再答： 不客气