r^2-10r-144=0

Solution for r^2-10r-144=0 equation:

r^2-10r-144=0

a = 1; b = -10; c = -144;
Δ = b2-4ac
Δ = -102-4·1·(-144)
Δ = 676
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$r_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$r_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{676}=26$
$r_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-10)-26}{2*1}=\frac{-16}{2}
=-8
$
$r_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-10)+26}{2*1}=\frac{36}{2}
=18
$