Answer
$c=9$
Work Step by Step
The given equation is
$\Rightarrow 1-\sqrt{c}=-2$
Add $2+\sqrt c$ to each side.
$\Rightarrow 1-\sqrt{c}+2+\sqrt c=-2+2+\sqrt c$
Simplify.
$\Rightarrow 3=\sqrt c$
Square each side of the equation.
$\Rightarrow 3^2=(\sqrt{c})^2$
Simplify.
$\Rightarrow 9=c$
Check $c=9$.
$\Rightarrow 1-\sqrt{c}=-2$
$\Rightarrow 1-\sqrt{9}=-2$
$\Rightarrow 1-3=-2$
$\Rightarrow -2=-2$
True.
Hence, the solution is $c=9$.
