3х в квадрате -7х-6 меньше 0
3x^2+7x-6=0
D=b^2-4ac = 7^2-4*3*(-6)=49-(-72)=49+72=121
VD=V121=11
-b+ - VD
Xo = --------------------
2a
x1 = (-7+11)/2*3 = 4/6 = 2/3
x2 = (-7-11)/2*3 = -18/6 = -3
OTBET: x=-3 i x=2/3