5x^2+13x-21=-4

Solution for 5x^2+13x-21=-4 equation:

5x^2+13x-21=-4

We move all terms to the left:

5x^2+13x-21-(-4)=0

We add all the numbers together, and all the variables

5x^2+13x-17=0

a = 5; b = 13; c = -17;
Δ = b2-4ac
Δ = 132-4·5·(-17)
Δ = 509
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{-(13)-\sqrt{509}}{2*5}=\frac{-13-\sqrt{509}}{10}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(13)+\sqrt{509}}{2*5}=\frac{-13+\sqrt{509}}{10}
$