(28-2x)(10-2x)=144

Solution for (28-2x)(10-2x)=144 equation:

(28-2x)(10-2x)=144

We move all terms to the left:

(28-2x)(10-2x)-(144)=0

We add all the numbers together, and all the variables

(-2x+28)(-2x+10)-144=0

We multiply parentheses ..

(+4x^2-20x-56x+280)-144=0

We get rid of parentheses

4x^2-20x-56x+280-144=0

We add all the numbers together, and all the variables

4x^2-76x+136=0

a = 4; b = -76; c = +136;
Δ = b2-4ac
Δ = -762-4·4·136
Δ = 3600
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{3600}=60$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-76)-60}{2*4}=\frac{16}{8}
=2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-76)+60}{2*4}=\frac{136}{8}
=17
$