用配方法做 6x²—7x+1=o 5x²-18=9x 4x²-3x=52 5x²=4-2x

用配方法做 6x²—7x+1=o 5x²-18=9x 4x²-3x=52 5x²=4-2x
用配方法做 6x²—7x+1=o 5x²-18=9x 4x²-3x=52 5x²=4-2x

用配方法做 6x²—7x+1=o 5x²-18=9x 4x²-3x=52 5x²=4-2x
6x²-7x+1=0
6(x²-7/6x+49/144)-6*49/144+1=0
6(x-7/12)²=150/144
(x-7/12)²=25/144
x-7/12=±5/12
x=7/12±5/12
x=1或x=1/6
5x²-18=9x
5x²-9x-18=0
5(x²-9/5x+81/100)-5*81/100-18=0
5(x-9/10)²=441/20
(x-9/10)²=441/100
x-9/10=±21/10
x=9/10±21/10
x=3或x=-6/5
4x²-3x=52
4(x²-3/4x+9/64)=52+4*9/64
4(x-3/8)²=841/16
(x-3/8)²=841/64
x-3/8=±29/8
x=3/8±29/8
x=4或x=-13/4
5x²=4-2x
5x²+2x=4
5(x²+2/5x+1/25)=4+5*1/25
5(x+1/5)²=21/5
(x+1/5)²=21/25
x+1/5=±√21/ 5
x=-1/5±√21/ 5
x=(-1+√21)/5或x=(-1-√21)/5