91Ó°ÊÓ

Find the value of each expression.

50. $\mathbf{8}\mathbf{+}\left(\mathbf{-}\mathbf{5}\right)$

Use a graphing calculator to find the value of the following determinant.

$\left|\begin{array}{cc}3& -6.5\\ 8& 3.75\\ & \end{array}\right|$

Solve each system of equations.

$\begin{array}{l}2a+b=2\\ 5a=15\\ a+b+c=−1\end{array}$

Solve each equation.50

$\left[\begin{array}{c}3\text{x}+2\\ 15\end{array}\right]=\left[\begin{array}{c}23\\ −4\text{y}−1\end{array}\right]$

Solve each system of equations by graphing.

50.

$\begin{array}{l}\mathbf{x}−\mathbf{2}\mathbf{y}=\mathbf{10}\\ \mathbf{2}\mathbf{x}−\mathbf{4}\mathbf{y}=\mathbf{12}\end{array}$

Perform the indicated matrix operations. If the matrix does not exist, write impossible.

$4\left[\begin{array}{ccc}3& 4& −7\\ 6& −9& −2\\ −3& 1& 3\end{array}\right]−\left[\begin{array}{ccc}−8& 6& −4\\ −7& 10& 1\\ −2& 1& 5\end{array}\right]$

Use a graphing calculator to find the inverse of each matrix.

50.

Solve each system of equations.

$\begin{array}{c}r+s+t=15\\ r+t=12\\ s+t=10\end{array}$

Find the value of each expression.

$\mathbf{-}\mathbf{2}\mathbf{-}\mathbf{8}$

The Friendly Fix-It Company charges a base fee of \(35 for any in-home repair. In addition, the technician charges \)10 per hour. Write an equation for the cost $\mathbf{c}$of an in-home repair of$\mathbf{h}$hours.