-5r(r+7)=-92

Solution for -5r(r+7)=-92 equation:

-5r(r+7)=-92

We move all terms to the left:

-5r(r+7)-(-92)=0

We add all the numbers together, and all the variables

-5r(r+7)+92=0

We multiply parentheses

-5r^2-35r+92=0

a = -5; b = -35; c = +92;
Δ = b2-4ac
Δ = -352-4·(-5)·92
Δ = 3065
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$r_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$r_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$r_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-35)-\sqrt{3065}}{2*-5}=\frac{35-\sqrt{3065}}{-10}
$
$r_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-35)+\sqrt{3065}}{2*-5}=\frac{35+\sqrt{3065}}{-10}
$