(7x+16)(4x+16)=360

Solution for (7x+16)(4x+16)=360 equation:

(7x+16)(4x+16)=360

We move all terms to the left:

(7x+16)(4x+16)-(360)=0

We multiply parentheses ..

(+28x^2+112x+64x+256)-360=0

We get rid of parentheses

28x^2+112x+64x+256-360=0

We add all the numbers together, and all the variables

28x^2+176x-104=0

a = 28; b = 176; c = -104;
Δ = b2-4ac
Δ = 1762-4·28·(-104)
Δ = 42624
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:

$\sqrt{\Delta}=\sqrt{42624}=\sqrt{576*74}=\sqrt{576}*\sqrt{74}=24\sqrt{74}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(176)-24\sqrt{74}}{2*28}=\frac{-176-24\sqrt{74}}{56}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(176)+24\sqrt{74}}{2*28}=\frac{-176+24\sqrt{74}}{56}
$