21x^2-52x-60=0

Solution for 21x^2-52x-60=0 equation:

21x^2-52x-60=0

a = 21; b = -52; c = -60;
Δ = b2-4ac
Δ = -522-4·21·(-60)
Δ = 7744
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{7744}=88$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-52)-88}{2*21}=\frac{-36}{42}
=-6/7
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-52)+88}{2*21}=\frac{140}{42}
=3+1/3
$