90=(7x-19)(x+5)

Solution for 90=(7x-19)(x+5) equation:

90=(7x-19)(x+5)

We move all terms to the left:

90-((7x-19)(x+5))=0

We multiply parentheses ..

-((+7x^2+35x-19x-95))+90=0


We calculate terms in parentheses: -((+7x^2+35x-19x-95)), so:

(+7x^2+35x-19x-95)

We get rid of parentheses

7x^2+35x-19x-95

We add all the numbers together, and all the variables

7x^2+16x-95

Back to the equation:

-(7x^2+16x-95)


We get rid of parentheses

-7x^2-16x+95+90=0

We add all the numbers together, and all the variables

-7x^2-16x+185=0

a = -7; b = -16; c = +185;
Δ = b2-4ac
Δ = -162-4·(-7)·185
Δ = 5436
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:

$\sqrt{\Delta}=\sqrt{5436}=\sqrt{36*151}=\sqrt{36}*\sqrt{151}=6\sqrt{151}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-16)-6\sqrt{151}}{2*-7}=\frac{16-6\sqrt{151}}{-14}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-16)+6\sqrt{151}}{2*-7}=\frac{16+6\sqrt{151}}{-14}
$