F(x)=x2-7x

Solution for F(x)=x2-7x equation:

(F)=F2-7F

We move all terms to the left:

(F)-(F2-7F)=0

We add all the numbers together, and all the variables

-(+F^2-7F)+F=0

We get rid of parentheses

-F^2+7F+F=0

We add all the numbers together, and all the variables

-1F^2+8F=0

a = -1; b = 8; c = 0;
Δ = b2-4ac
Δ = 82-4·(-1)·0
Δ = 64
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$F_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$F_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{64}=8$
$F_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(8)-8}{2*-1}=\frac{-16}{-2}
=+8
$
$F_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(8)+8}{2*-1}=\frac{0}{-2}
=0
$