-7x^2-48x+7=0

Solution for -7x^2-48x+7=0 equation:

-7x^2-48x+7=0

a = -7; b = -48; c = +7;
Δ = b2-4ac
Δ = -482-4·(-7)·7
Δ = 2500
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{2500}=50$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-48)-50}{2*-7}=\frac{-2}{-14}
=1/7
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-48)+50}{2*-7}=\frac{98}{-14}
=-7
$