5c^2-21c+11=-4c

Solution for 5c^2-21c+11=-4c equation:

5c^2-21c+11=-4c

We move all terms to the left:

5c^2-21c+11-(-4c)=0

We get rid of parentheses

5c^2-21c+4c+11=0

We add all the numbers together, and all the variables

5c^2-17c+11=0

a = 5; b = -17; c = +11;
Δ = b2-4ac
Δ = -172-4·5·11
Δ = 69
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{-(-17)-\sqrt{69}}{2*5}=\frac{17-\sqrt{69}}{10}
$
$c_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-17)+\sqrt{69}}{2*5}=\frac{17+\sqrt{69}}{10}
$