0=5x^2-4x-672

Solution for 0=5x^2-4x-672 equation:

0=5x^2-4x-672

We move all terms to the left:

0-(5x^2-4x-672)=0

We add all the numbers together, and all the variables

-(5x^2-4x-672)=0

We get rid of parentheses

-5x^2+4x+672=0

a = -5; b = 4; c = +672;
Δ = b2-4ac
Δ = 42-4·(-5)·672
Δ = 13456
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{13456}=116$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(4)-116}{2*-5}=\frac{-120}{-10}
=+12
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(4)+116}{2*-5}=\frac{112}{-10}
=-11+1/5
$