(x+49)(2x)=90

Solution for (x+49)(2x)=90 equation:

(x+49)(2x)=90

We move all terms to the left:

(x+49)(2x)-(90)=0

We multiply parentheses

2x^2+98x-90=0

a = 2; b = 98; c = -90;
Δ = b2-4ac
Δ = 982-4·2·(-90)
Δ = 10324
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:

$\sqrt{\Delta}=\sqrt{10324}=\sqrt{4*2581}=\sqrt{4}*\sqrt{2581}=2\sqrt{2581}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(98)-2\sqrt{2581}}{2*2}=\frac{-98-2\sqrt{2581}}{4}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(98)+2\sqrt{2581}}{2*2}=\frac{-98+2\sqrt{2581}}{4}
$