Given the equation:

To find the value of 'c', the first step to do is to get rid of the parenthesis. We can do this using the distributive property on both cases:

Now that we don't have any parenthesis in our equation, we start moving similar terms: we leave on the left the terms with the variable 'c' and we move the rest of the terms to the right side with it's sign changed:

We can make the operations on each side since now we have the similar terms apart:

Finally, we move the -4 that is multiplying the 'c' to the other side doing its opposite operation:

therefore, c=-11