x2+1.3x-7.7=0

Solution for x2+1.3x-7.7=0 equation:

x2+1.3x-7.7=0

We add all the numbers together, and all the variables

x^2+1.3x-7.7=0

a = 1; b = 1.3; c = -7.7;
Δ = b2-4ac
Δ = 1.32-4·1·(-7.7)
Δ = 32.49
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{-(1.3)-\sqrt{32.49}}{2*1}=\frac{-1.3-\sqrt{32.49}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(1.3)+\sqrt{32.49}}{2*1}=\frac{-1.3+\sqrt{32.49}}{2}
$