-16x^2+28x+72=0

Solution for -16x^2+28x+72=0 equation:

-16x^2+28x+72=0

a = -16; b = 28; c = +72;
Δ = b2-4ac
Δ = 282-4·(-16)·72
Δ = 5392
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{5392}=\sqrt{16*337}=\sqrt{16}*\sqrt{337}=4\sqrt{337}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(28)-4\sqrt{337}}{2*-16}=\frac{-28-4\sqrt{337}}{-32}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(28)+4\sqrt{337}}{2*-16}=\frac{-28+4\sqrt{337}}{-32}
$