(2x+8)(7x+1)=0

Solution for (2x+8)(7x+1)=0 equation:

(2x+8)(7x+1)=0

We multiply parentheses ..

(+14x^2+2x+56x+8)=0

We get rid of parentheses

14x^2+2x+56x+8=0

We add all the numbers together, and all the variables

14x^2+58x+8=0

a = 14; b = 58; c = +8;
Δ = b2-4ac
Δ = 582-4·14·8
Δ = 2916
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{2916}=54$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(58)-54}{2*14}=\frac{-112}{28}
=-4
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(58)+54}{2*14}=\frac{-4}{28}
=-1/7
$