7.1: Systems of Linear Equations in Two Variables

Warm-up:

1. Solve the following system of equations using substitution. Then solve it using elimination. Then solve it system graphically using Desmos.

\[
\left\{\begin{array}{l}
3 x+y=9 \\
-2 x+y=4
\end{array}\right.
\]

2. Solve the following systems of equations using elimination:

(a)

\[
\left\{\begin{array}{l}
-4 R-7 T=14 \\
3 R+14 T=2
\end{array}\right.
\]

(b)

\[
\left\{\begin{array}{l}
6 x+5 y=12 \\
2 x-7 y=6
\end{array}\right.
\]

3. Solve the following systems of equations using substitution:

(a)

\[
\left\{\begin{array}{l}
2 x+6 y=8 \\
x-7 y=14
\end{array}\right.
\]

(b)

\[
\left\{\begin{array}{l}
2 A-4 B=10 \\
4 A+5 B=-6
\end{array}\right.
\]

4. Solve the following system of equations graphically:

\[
\left\{\begin{array}{l}
3 x+6 y=18 \\
-x+2 y=4
\end{array}\right.
\]

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