9.1

Solve the equations by graphing:

a)

$\begin{array}{ccc}\hfill I-3x-5y& =-30\hfill & \hfill \\ \hfill II-x-5y& =-10\hfill \end{array}$

b)

$\begin{array}{ccc}\hfill I-x-4y& =-8\hfill & \hfill \\ \hfill II-2x+y& =-7\hfill \end{array}$

c)

$\begin{array}{ccc}\hfill I-2x-y& =-7\hfill & \hfill \\ \hfill II-2x+y& =-1\hfill \end{array}$

d)

$\begin{array}{ccc}\hfill I-2x+y& =4\hfill & \hfill \\ \hfill IIx+y& =4\hfill \end{array}$

9.2)

Solve the equations with the substitution method:

a)

$\begin{array}{ccc}\hfill I-2x-5y& =-30\hfill & \hfill \\ \hfill II-2x+y& =-6\hfill \end{array}$

b)

$\begin{array}{ccc}\hfill I-x-y& =-4\hfill & \hfill \\ \hfill II-6x+y& =-38\hfill \end{array}$

c)

$\begin{array}{ccc}\hfill I3x-2y& =18\hfill & \hfill \\ \hfill IIx+y& =16\hfill \end{array}$

d)

$\begin{array}{ccc}\hfill I2x-y& =-3\hfill & \hfill \\ \hfill II3x+y& =18\hfill \end{array}$

9.3)

Solve the equations with the elimination method:

a)

$\begin{array}{ccc}\hfill I-x-3y& =-23\hfill & \hfill \\ \hfill IIx+y& =-3\hfill \end{array}$

b)

$\begin{array}{ccc}\hfill I-x+y& =-1\hfill & \hfill \\ \hfill II-3x+y& =-7\hfill \end{array}$

c)

$\begin{array}{ccc}\hfill I-2x+y& =-6\hfill & \hfill \\ \hfill II-x-3y& =-17\hfill \end{array}$

d)

$\begin{array}{ccc}\hfill I-x+y& =4\hfill & \hfill \\ \hfill IIx+9y& =46\hfill \end{array}$

You can find the solutions here.