-10x^2+28x+6=0

Solution for -10x^2+28x+6=0 equation:

-10x^2+28x+6=0

a = -10; b = 28; c = +6;
Δ = b2-4ac
Δ = 282-4·(-10)·6
Δ = 1024
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1024}=32$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(28)-32}{2*-10}=\frac{-60}{-20}
=+3
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(28)+32}{2*-10}=\frac{4}{-20}
=-1/5
$