C(x)=-0.00002x^2-0.04x+49

Solution for C(x)=-0.00002x^2-0.04x+49 equation:

(C)=-0.00002C^2-0.04C+49

We move all terms to the left:

(C)-(-0.00002C^2-0.04C+49)=0

We get rid of parentheses

0.00002C^2+0.04C+C-49=0

We add all the numbers together, and all the variables

0.00002C^2+1.04C-49=0

a = 0.00002; b = 1.04; c = -49;
Δ = b2-4ac
Δ = 1.042-4·0.00002·(-49)
Δ = 1.08552
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$C_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$C_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$C_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(1.04)-\sqrt{1.08552}}{2*0.00002}=\frac{-1.04-\sqrt{1.08552}}{5.87312731384}
$
$C_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(1.04)+\sqrt{1.08552}}{2*0.00002}=\frac{-1.04+\sqrt{1.08552}}{5.87312731384}
$