0=-16x^2-21x-6

Solution for 0=-16x^2-21x-6 equation:

0=-16x^2-21x-6

We move all terms to the left:

0-(-16x^2-21x-6)=0

We add all the numbers together, and all the variables

-(-16x^2-21x-6)=0

We get rid of parentheses

16x^2+21x+6=0

a = 16; b = 21; c = +6;
Δ = b2-4ac
Δ = 212-4·16·6
Δ = 57
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{-(21)-\sqrt{57}}{2*16}=\frac{-21-\sqrt{57}}{32}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(21)+\sqrt{57}}{2*16}=\frac{-21+\sqrt{57}}{32}
$