Chapter 3 - Solving Inequalities - 3-2 Solving Inequalities Using Addition or Subtraction - Practice and Problem-Solving Exercises - Page 174: 27

$c$

You need to isolate the variable $c$. To do this you're going to add the $\frac{4}{7}$ to both sides of the equation. This will cancel out the $-\frac{4}{7}$ on the side with the $c$ and isolate the variable. You're also going to balance the equation by adding $\frac{4}{7}$ to the other side with the $\frac{6}{7}$, giving us $\frac{10}{7}$ on the other side and resulting in our answer of $c$