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

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