-a(7a+5)=-160

Solution for -a(7a+5)=-160 equation:

-a(7a+5)=-160

We move all terms to the left:

-a(7a+5)-(-160)=0

We add all the numbers together, and all the variables

-a(7a+5)+160=0

We multiply parentheses

-7a^2-5a+160=0

a = -7; b = -5; c = +160;
Δ = b2-4ac
Δ = -52-4·(-7)·160
Δ = 4505
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-5)-\sqrt{4505}}{2*-7}=\frac{5-\sqrt{4505}}{-14}
$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-5)+\sqrt{4505}}{2*-7}=\frac{5+\sqrt{4505}}{-14}
$