Question

2X的平方－3X－6＝0用配方法怎么算？

Answer 1

2X的平方－3X－6＝0用配方法怎么算 2x²-3x-6=0，x²-3x/2-3=0，x²-2×3x/4+9/16-9/16-3=0，(x-3/4)²-9/16-3=0，(x-3/4)²=57/16，解得x-3/4=±√57/4，即x=(3±√57)/4 2x²-3x-6=0x² - 3/2 x - 3 =0x² - 3/2 x + 9/16 = 3 + 9/16(x -3/4)² = 57/16x -3/4 = ±√57 /4x = (3±√57) / 4 2X²-3X-6=0X²-1.5X=3（X-0.75）²=3+0.75²（X-0.75）²=57/16X-0.75=±根号57/4X1=0.75+根号57/4X2=0.75-根号57/4

Answer 2

2X的平方－3X－6＝0用配方法怎么算 2x²-3x-6=0，x²-3x/2-3=0，x²-2×3x/4+9/16-9/16-3=0，(x-3/4)²-9/16-3=0，(x-3/4)²=57/16，解得x-3/4=±√57/4，即x=(3±√57)/4 2x²-3x-6=0x² - 3/2 x - 3 =0x² - 3/2 x + 9/16 = 3 + 9/16(x -3/4)² = 57/16x -3/4 = ±√57 /4x = (3±√57) / 4 2X²-3X-6=0X²-1.5X=3（X-0.75）²=3+0.75²（X-0.75）²=57/16X-0.75=±根号57/4X1=0.75+根号57/4X2=0.75-根号57/4

Answer 3

2x²-3x-6=0
x²-1.5x=3
x²-2×¾x+(¾)²=3+(¾)²
（x-¾）²=57/16
x=¾±(√57/4)

∴x=(3+√57)/4或(3-√57)/4