13x^2-47x-20=0

Solution for 13x^2-47x-20=0 equation:

13x^2-47x-20=0

a = 13; b = -47; c = -20;
Δ = b2-4ac
Δ = -472-4·13·(-20)
Δ = 3249
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{3249}=57$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-47)-57}{2*13}=\frac{-10}{26}
=-5/13
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-47)+57}{2*13}=\frac{104}{26}
=4
$