210=c+10+c2+c

Solution for 210=c+10+c2+c equation:

210=c+10+c2+c

We move all terms to the left:

210-(c+10+c2+c)=0

We add all the numbers together, and all the variables

-(+2c+c^2+10)+210=0

We get rid of parentheses

-c^2-2c-10+210=0

We add all the numbers together, and all the variables

-1c^2-2c+200=0

a = -1; b = -2; c = +200;
Δ = b2-4ac
Δ = -22-4·(-1)·200
Δ = 804
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$c_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$c_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{804}=\sqrt{4*201}=\sqrt{4}*\sqrt{201}=2\sqrt{201}$
$c_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-2)-2\sqrt{201}}{2*-1}=\frac{2-2\sqrt{201}}{-2}
$
$c_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-2)+2\sqrt{201}}{2*-1}=\frac{2+2\sqrt{201}}{-2}
$