x^2-7x-690=0

Solution for x^2-7x-690=0 equation:

x^2-7x-690=0

a = 1; b = -7; c = -690;
Δ = b2-4ac
Δ = -72-4·1·(-690)
Δ = 2809
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{2809}=53$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-7)-53}{2*1}=\frac{-46}{2}
=-23
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-7)+53}{2*1}=\frac{60}{2}
=30
$