Question

Use a graph and a table to solve the system. Check your answer.
Enter your answer as an ordered pair, like this: (3, -12)
3x+y=-12
x+3y=4

Answer 1

Make a table like so:
\[\begin{array}{|c|c|}
\hline
x &y\\
\hline
1&?\\
\hline
0&?\\
\hline
-1&?\\
\hline
\end{array}\]

\[3x+y=-12 \Rightarrow y = -12 - 3x\]
Sub in the \(x\) values.
Record the \(y\) values, then plot the points.
Draw a line through these points, the line should be linear.

Do the same for the second equation, where the lines intersect is the solution.

Answer 2

@Opcode² how?

Answer 3

You see how I converted \(3x + y = -12\) to \(y = mx + d\) form?
\[3x + y = -12 \Rightarrow y = -3x - 12\]
In the table I gave I listed random values for \(x\).
Simple sub in those values to get the value of \(y\) that corresponds with \(x\).
Say:
\[x = 1\]
\[y = -3(1) - 12\]
\[y = -3 - 12\]
\[y = -15\]

So when \(x\) equals 1, \(y\) equals -15.

Do this a few more times till you can see the linear pattern in the points then draw a line through them, do this for the second equation as well. Were the lines intersect (cross) that is your solution.)