x(x+2)(2.5)=210

Solution for x(x+2)(2.5)=210 equation:

x(x+2)(2.5)=210

We move all terms to the left:

x(x+2)(2.5)-(210)=0

We multiply parentheses ..

x(+2.5x+5)-210=0

We add all the numbers together, and all the variables

x(2.5x+5)-210=0

We multiply parentheses

2x^2+5x-210=0

a = 2; b = 5; c = -210;
Δ = b2-4ac
Δ = 52-4·2·(-210)
Δ = 1705
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{1705}}{2*2}=\frac{-5-\sqrt{1705}}{4}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(5)+\sqrt{1705}}{2*2}=\frac{-5+\sqrt{1705}}{4}
$