1.2x2-0.7x-1=0

Solution for 1.2x2-0.7x-1=0 equation:

1.2x^2-0.7x-1=0

a = 1.2; b = -0.7; c = -1;
Δ = b2-4ac
Δ = -0.72-4·1.2·(-1)
Δ = 5.29
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-0.7)-\sqrt{5.29}}{2*1.2}=\frac{0.7-\sqrt{5.29}}{2.4}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-0.7)+\sqrt{5.29}}{2*1.2}=\frac{0.7+\sqrt{5.29}}{2.4}
$