2*(x*x)-3x-9=5

Solution for 2*(x*x)-3x-9=5 equation:

2(x*x)-3x-9=5

We move all terms to the left:

2(x*x)-3x-9-(5)=0

We add all the numbers together, and all the variables

2(+x*x)-3x-9-5=0

We add all the numbers together, and all the variables

-3x+2(+x*x)-14=0

We multiply parentheses

2x^2-3x-14=0

a = 2; b = -3; c = -14;
Δ = b2-4ac
Δ = -32-4·2·(-14)
Δ = 121
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{121}=11$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-3)-11}{2*2}=\frac{-8}{4}
=-2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-3)+11}{2*2}=\frac{14}{4}
=3+1/2
$