30=2x2+7x

Solution for 30=2x2+7x equation:

30=2x^2+7x

We move all terms to the left:

30-(2x^2+7x)=0

We get rid of parentheses

-2x^2-7x+30=0

a = -2; b = -7; c = +30;
Δ = b2-4ac
Δ = -72-4·(-2)·30
Δ = 289
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{289}=17$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-7)-17}{2*-2}=\frac{-10}{-4}
=2+1/2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-7)+17}{2*-2}=\frac{24}{-4}
=-6
$