Linear Algebra

Here's how I solved it

$$\begin{array}{lcl}
e = 2\frac{1}{2} = \frac{4}{2} + \frac{1}{2} = \frac{5}{2}\\
f = 3\frac{1}{3} = \frac{9}{3} + \frac{1}{3} = \frac{10}{3}\\
4e-2f = 4*\frac{5}{2} - 2*\frac{10}{3}\\
= \frac{20}{2} - \frac{20}{3}\\
= \frac{20}{2} * 1 - \frac{20}{3} * 1\\
= \frac{20}{2} * \frac{3}{3} - \frac{20}{3} * \frac{2}{2}\\
= \frac{60}{6} - \frac{40}{6}\\
= \frac{60-40}{6}\\
= \frac{20}{6}\\
= \frac{10}{3}\\
= 3 \frac{1}{3}
\end{array}$$

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