134=2*x^2+3*x+15

Solution for 134=2*x^2+3*x+15 equation:

134=2x^2+3x+15

We move all terms to the left:

134-(2x^2+3x+15)=0

We get rid of parentheses

-2x^2-3x-15+134=0

We add all the numbers together, and all the variables

-2x^2-3x+119=0

a = -2; b = -3; c = +119;
Δ = b2-4ac
Δ = -32-4·(-2)·119
Δ = 961
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{961}=31$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-3)-31}{2*-2}=\frac{-28}{-4}
=+7
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-3)+31}{2*-2}=\frac{34}{-4}
=-8+1/2
$