Answer
$x=\dfrac{3}{8}$
Work Step by Step
With $f(x)=-\frac{7}{16}$, substitute $-\frac{7}{16}$ to $f(x)$ to obtain:
$$-\dfrac{7}{16}=\dfrac{5}{6}x-\dfrac{3}{4}$$
Multiply $48$ to both sides of the equation to eliminate the fractions:
$$\begin{align*}
48\left(-\dfrac{7}{16}\right)&=\left(\dfrac{5}{6}x-\dfrac{3}{4}\right)\cdot 48\\
-21&=40x-36
\end{align*}$$
Add $36$ to both sdies:
$$\begin{align*}
-21+36&=40x-36+36\\
15&=40x
\end{align*}$$
Divide $40$ to both sides:
$$\begin{align*}
\frac{15}{40}&=\frac{40x}{40}\\
\frac{3}{8}&=x
\end{align*}$$