Answer
$ c=-42$.
Work Step by Step
The given equation is
$\Rightarrow 6=\frac{c}{-7}$
Multiply each side by $-7$.
$\Rightarrow -7\cdot 6=-7\cdot \frac{c}{-7}$
Simplify.
$\Rightarrow -42=c$
Check:- $c=-42$
$\Rightarrow 6=\frac{-42}{-7}$
$\Rightarrow 6=6$
True.
Hence, the solution is $c=-42$.
