13. A youth club receives a discount on each pizza purchased for a party. The original price of each pizza is \( x \) dollars. The club leader purchases 8 pizzas for a total of \( (8 x-32) \) dollars. Factor the expression. What can you conclude about the discount? 14. Three crates of food are packed on a shuttle departing for the Moon. Each crate weighs \( x \) pounds. On the Moon, the combined weight of the crates is ( \( 3 x-81) \) pounds. What can you conclude about the weight of each crate on the Moon?

\( 1 \leftarrow \quad \begin{array}{l}\text { Solve the system of equations by the substitution method. } \\ \begin{aligned} 4 x+2 y & =-154 \\ x-5 y & =0\end{aligned}\end{array} \)

\( 1<\quad \begin{array}{r}\text { Determine whether the ordered pair }(4,5) \text { is a solution of the system. } \\ \begin{array}{r}3 x+2 y=2 \\ 2 x+y=3\end{array}\end{array} \)

\( 8 x y \) is a monomial expression. Is the statement true or fause?

\( 1 \leftarrow \quad \begin{array}{l}\text { Determine whether the ordered pair }(3,4) \text { is a solution of the system. } \\ \begin{array}{l}x+y=7 \\ x-y=-1\end{array}\end{array} \)

What should be, subtracted from \( 8 x-3 y+4 \) to get \( 3 x-2 y+4 \).