Answer:

Step-by-step explanation:
<em><u>Given:</u></em>
A quadratic equation:
, with
is a solution.
<em><u>Solve for:</u></em>
Value of c
<em><u>Step 1: define the problem</u></em>
If
is a solution of equation
, then 
<em><u>Step 2: Perform the calculation</u></em>
Substitute
into original quadratic equation, we have:

Perform the square and multiplication:

Transfer all of numbers to the right side, except c:
(notice for the change in sign of numbers)

Perform the sum on the right side to get c:

Hope this helps!
:)