F(-1)=2x^2-13x+15

Solution for F(-1)=2x^2-13x+15 equation:

(-1)=2F^2-13F+15

We move all terms to the left:

(-1)-(2F^2-13F+15)=0

We add all the numbers together, and all the variables

-(2F^2-13F+15)-1=0

We get rid of parentheses

-2F^2+13F-15-1=0

We add all the numbers together, and all the variables

-2F^2+13F-16=0

a = -2; b = 13; c = -16;
Δ = b2-4ac
Δ = 132-4·(-2)·(-16)
Δ = 41
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$F_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$F_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$F_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(13)-\sqrt{41}}{2*-2}=\frac{-13-\sqrt{41}}{-4}
$
$F_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(13)+\sqrt{41}}{2*-2}=\frac{-13+\sqrt{41}}{-4}
$