-16x2+18x+28=0

Solution for -16x2+18x+28=0 equation:

-16x^2+18x+28=0

a = -16; b = 18; c = +28;
Δ = b2-4ac
Δ = 182-4·(-16)·28
Δ = 2116
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{2116}=46$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(18)-46}{2*-16}=\frac{-64}{-32}
=+2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(18)+46}{2*-16}=\frac{28}{-32}
=-7/8
$