30+2.5x(2)=200

Solution for 30+2.5x(2)=200 equation:

30+2.5x(2)=200

We move all terms to the left:

30+2.5x(2)-(200)=0

We add all the numbers together, and all the variables

2.5x^2-170=0

a = 2.5; b = 0; c = -170;
Δ = b2-4ac
Δ = 02-4·2.5·(-170)
Δ = 1700
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:

$\sqrt{\Delta}=\sqrt{1700}=\sqrt{100*17}=\sqrt{100}*\sqrt{17}=10\sqrt{17}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-10\sqrt{17}}{2*2.5}=\frac{0-10\sqrt{17}}{5}
=-\frac{10\sqrt{17}}{5}
=-2\sqrt{17}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+10\sqrt{17}}{2*2.5}=\frac{0+10\sqrt{17}}{5}
=\frac{10\sqrt{17}}{5}
=2\sqrt{17}
$