Solve the given system by the substitution method. If there is no solution or an infinite number of solution \( \left\{\begin{array}{l}y=5 x-7 \\ 15 x-21=3 y\end{array}\right. \) Select the correct choice below and, if necessary, fill in the answer box to complete your choice. A. There is exactly one solution. The solution set is \( \} \). (Type an ordered pair, using integers or fractions. Simplify your answer.) B. There are infinitely many solutions. The solution set is \( \{(x, y) \mid y=5 x-7\} \) or \( \{(x, y) \mid 15 x-21=3 y\} \). C. There is no solution. The solution set is the empty set, \( \varnothing \).

6 A delivery truck was valued at \( \$ 65000 \) when new. The value of the truck depreciates at a rate of 22 cents per kilometre travelled. What is the value of the truck after it has travelled a total distance of 132600 km ? A. \( \$ 35828 \) B. \( \$ 29172 \) C. \( \$ 14872 \) D. \( \$ 14300 \)

Simplify. \[ 3(4 x+2)-8 \]

Find the midpoint of the segment with the following endpoints. \( (5,7) \) and \( (-3,10) \)

Question 5 The matrices \( \mathbf{A} \) and \( \mathbf{B} \) are given by \( \mathbf{A}=\left(\begin{array}{lll}2 & 1 & 1 \\ 1 & 1 & 1 \\ 2 & 2 & 1\end{array}\right), \mathbf{B}=\left(\begin{array}{lrr}2 & -2 & 0 \\ -2 & 0 & 2 \\ 0 & 4 & -2\end{array}\right) \)

Compute each of the following. \( \begin{array}{ll}\text { a. }(-2)^{3} & \text { b. }(-3)^{4} \\ \text { c. }(-10)^{4} \div(-10)^{2} & \text { d. }(-2)^{5} \div(-2) \\ \text { e. }(-1)^{46} & \text { f. }(-1)^{151} \\ \text { g. }-3+5 \cdot 2-1 & \text { h. } 10-2 \cdot 6-4(-3)+4 \\ \text { i. }(-2)^{66}-2^{66} & \text { j. }-2^{10}+2^{10}\end{array} \)