(2x-9)(x=39)

Solution for (2x-9)(x=39) equation:

(2x-9)(x=39)

We move all terms to the left:

(2x-9)(x-(39))=0

We multiply parentheses ..

(+2x^2-78x-9x+351)=0

We get rid of parentheses

2x^2-78x-9x+351=0

We add all the numbers together, and all the variables

2x^2-87x+351=0

a = 2; b = -87; c = +351;
Δ = b2-4ac
Δ = -872-4·2·351
Δ = 4761
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{4761}=69$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-87)-69}{2*2}=\frac{18}{4}
=4+1/2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-87)+69}{2*2}=\frac{156}{4}
=39
$