- 1). Plug your given slope "m" and point (x1,y1) into the point-slope form to convert it into slope-intercept form. Use the slope-intercept form to find additional points on the line and use these and the slope to graph the line.
- 2). Graph a line that has a slope of 3 and passes through the point (-2, -4). Plug the given information into the point-slope equation:
y - (-4) = 3 (x - (-2)), or
y + 4 = 3 (x + 2).
Multiply the "3" through the parentheses:
y + 4 = 3x + 2.
Subtract 4 from both sides to isolate the variable and set it into slope-intercept form:
y = 3x + -2.
Note that we now know the slope (m= 3) as well as the y-intercept (b = -2). - 3). Find the x-intercept of the line by setting the "y" in the slope-intercept equation equal to zero:
0 = 3x + -2.
Add 2 to both sides to get:
2 = 3x.
Divide both sides by 3:
1.5 = x.
Write out the y- and x-intercepts as coordinate points: (0, -2) and (1.5, 0). - 4). Find an additional point on the line. Since a slope of 3 (which is equal to 3/1) means that you have to rise (go up) three and run (go right) one, from the known point (0, -2) you can calculate the point (1 , 1). Repeat this process with another point if you need more help seeing where the line goes.
- 5). Draw dark dots on the graph at the known points of (-2, -4), (0, -2), (1.5, 0) and (1, 1). Line the ruler up along the edges of the dots and draw in the line, drawing arrows on each end to indicate that it continues in both directions.
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