求大神用配方法,

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求大神用配方法,求大神用配方法, 求大神用配方法,3x^2+6x-4=03(x^2+2x+1)-7=03(x+1)^2=7(x+1)^2=7/3x+1=√21/3或-√21/3x=√21/3

求大神用配方法,
求大神用配方法,
 

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