F(x)=-2/5x-3

Solution for F(x)=-2/5x-3 equation:

(F)=-2/5F-3

We move all terms to the left:

(F)-(-2/5F-3)=0


Domain of the equation: 5F-3)!=0

F∈R


We get rid of parentheses

F+2/5F+3=0

We multiply all the terms by the denominator


F*5F+3*5F+2=0

Wy multiply elements

5F^2+15F+2=0

a = 5; b = 15; c = +2;
Δ = b2-4ac
Δ = 152-4·5·2
Δ = 185
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{-(15)-\sqrt{185}}{2*5}=\frac{-15-\sqrt{185}}{10}
$
$F_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(15)+\sqrt{185}}{2*5}=\frac{-15+\sqrt{185}}{10}
$