7x(x+4)=180

Solution for 7x(x+4)=180 equation:

7x(x+4)=180

We move all terms to the left:

7x(x+4)-(180)=0

We multiply parentheses

7x^2+28x-180=0

a = 7; b = 28; c = -180;
Δ = b2-4ac
Δ = 282-4·7·(-180)
Δ = 5824
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{5824}=\sqrt{64*91}=\sqrt{64}*\sqrt{91}=8\sqrt{91}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(28)-8\sqrt{91}}{2*7}=\frac{-28-8\sqrt{91}}{14}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(28)+8\sqrt{91}}{2*7}=\frac{-28+8\sqrt{91}}{14}
$