Question

How do you graph the equation `3x+7y=42`?

Answer 1

graph{3x+7y=42 [-10, 10, -5, 5]}

Explanation:

`7y=-2x+42` isolate y-term to put into slope-intercept form `y=mx+b`
`y=-2/7x + 6` divide by 7 to isolate y
Plot first point: (0,6). This is given by the equation, where `b=6`. This is your y-intercept, or where x equals 0 and the line crosses the y-axis.
Next, you want to use the slope to get your next point. Remember: the slope is rise over run. In other words, because your slope is `-2/7`, you want to RISE -2 (because this is a negative number, you will go down 2), and RUN 7 (because this is a positive number, you will go 7 to the right). Plot this point and connect the two points to give you your line.