Answer
The expression evaluates to $6$.
Work Step by Step
We first need to solve the equation to find out what $x$ is.
We will multiply the entire equation by the least common denominator in order to get rid of the fractions. The least common denominator is $4$, so we multiply the entire equation by $4$:
$$4(\frac{3x}{2}) + 4(\frac{3x}{4}) = 4(\frac{x}{4}) - 4(4)$$
Divide out common factors to get rid of the fractions:
$$6x + 3x = x - 16$$
Subtract $x$ from each side and combine like terms to get:
$$8x = -16$$
Solve for $x$:
$$x = -2$$
Now that we have the value for $x$, we can plug it into the expression $x^{2} - x$:
$$(-2)^{2} - (-2)$$
We square $2$ first to get:
$$4 - (-2)$$
A negative and a negative make a positive, so we can rewrite the equation as follows:
$$4 + 2$$
The expression evaluates to $6$.
