F(x)=10x2+9x-4

Solution for F(x)=10x2+9x-4 equation:

(F)=10F^2+9F-4

We move all terms to the left:

(F)-(10F^2+9F-4)=0

We get rid of parentheses

-10F^2+F-9F+4=0

We add all the numbers together, and all the variables

-10F^2-8F+4=0

a = -10; b = -8; c = +4;
Δ = b2-4ac
Δ = -82-4·(-10)·4
Δ = 224
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$F_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$F_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{224}=\sqrt{16*14}=\sqrt{16}*\sqrt{14}=4\sqrt{14}$
$F_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-8)-4\sqrt{14}}{2*-10}=\frac{8-4\sqrt{14}}{-20}
$
$F_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-8)+4\sqrt{14}}{2*-10}=\frac{8+4\sqrt{14}}{-20}
$