369=(30-4x)(16+2x)

Solution for 369=(30-4x)(16+2x) equation:

369=(30-4x)(16+2x)

We move all terms to the left:

369-((30-4x)(16+2x))=0

We add all the numbers together, and all the variables

-((-4x+30)(2x+16))+369=0

We multiply parentheses ..

-((-8x^2-64x+60x+480))+369=0


We calculate terms in parentheses: -((-8x^2-64x+60x+480)), so:

(-8x^2-64x+60x+480)

We get rid of parentheses

-8x^2-64x+60x+480

We add all the numbers together, and all the variables

-8x^2-4x+480

Back to the equation:

-(-8x^2-4x+480)


We get rid of parentheses

8x^2+4x-480+369=0

We add all the numbers together, and all the variables

8x^2+4x-111=0

a = 8; b = 4; c = -111;
Δ = b2-4ac
Δ = 42-4·8·(-111)
Δ = 3568
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:

$\sqrt{\Delta}=\sqrt{3568}=\sqrt{16*223}=\sqrt{16}*\sqrt{223}=4\sqrt{223}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(4)-4\sqrt{223}}{2*8}=\frac{-4-4\sqrt{223}}{16}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(4)+4\sqrt{223}}{2*8}=\frac{-4+4\sqrt{223}}{16}
$