X(5-2x)+15=0

Solution for X(5-2x)+15=0 equation:

X(5-2X)+15=0

We add all the numbers together, and all the variables

X(-2X+5)+15=0

We multiply parentheses

-2X^2+5X+15=0

a = -2; b = 5; c = +15;
Δ = b2-4ac
Δ = 52-4·(-2)·15
Δ = 145
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(5)-\sqrt{145}}{2*-2}=\frac{-5-\sqrt{145}}{-4}
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(5)+\sqrt{145}}{2*-2}=\frac{-5+\sqrt{145}}{-4}
$