三个解方程(1)X^2+10x+9=0(2)X^2-x-7\4=0(3)3X^2+6x-4=0
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![三个解方程(1)X^2+10x+9=0(2)X^2-x-7\4=0(3)3X^2+6x-4=0](/uploads/image/z/8622997-61-7.jpg?t=%E4%B8%89%E4%B8%AA%E8%A7%A3%E6%96%B9%E7%A8%8B%EF%BC%881%EF%BC%89X%5E2%2B10x%2B9%3D0%282%29X%5E2-x-7%5C4%3D0%283%293X%5E2%2B6x-4%3D0)
三个解方程(1)X^2+10x+9=0(2)X^2-x-7\4=0(3)3X^2+6x-4=0
三个解方程
(1)X^2+10x+9=0
(2)X^2-x-7\4=0
(3)3X^2+6x-4=0
三个解方程(1)X^2+10x+9=0(2)X^2-x-7\4=0(3)3X^2+6x-4=0
(1) x^2+10x+9=0
(x+9)(x+1)=0
x+9=0,x=-9
x+1=0,x=-1
(2) x^2-x-7/4=0
4x^2-4x-7=0
x1=(4+(16+16*7)^0.5)/8=(4+8*(2^0.5))/8=(1+2*(2^0.5))/2
x2=(4-(16+16*7)^0.5)/8=(4-8*(2^0.5))/8=(1-2*(2^0.5))/2
(3) 3x^2+6x-4=0
x1=(-6+(36+48)^0.5)/6=(-6+2*(21^0.5))/6=(-3+(21^0.5))/3
x2=(-6-(36+48)^0.5)/6=(-6-2*(21^0.5))/6=(-3-(21^0.5))/3