Tamara J. answered • 10/24/12
Math Tutoring - Algebra and Calculus (all levels)
The equation of the line in question is: y = 3x - 4 , which is in slope-intercept form.
Note that the general form of the slope-intercept equation is: y = mx + b , where m is the slope of the line (rise/run) and b is the y-intercept of the line (the point where x=0).
To see the equation of the line y = 3x - 4 more clearly, rewrite it as y = 3x + (-4).
Thus, we arrive at the following:
slope of the line: m = 3
y-intercept: b = -4
When graphing this line, first locate the y-intercept (0, -4). Then use the slope to find one to two points to the right and to the left of the point (0, -4). To find these points, use the rise/run method of the slope.
For points to the right of the y-intercept:
since the slope is m=3, this is equivalent to 3/1; that is, you go up the y-axis 3 points and to the right on the x-axis 1 point, which would would yield the point (1, -1).
For points to the left of the y-intercept:
since the slope is m=3 (which is equivalent to 3/1) it is also equivalent to -3/-1; that is, you go down the y-axis 3 points and to the left on the x-axis 1 point, which would yield the point (-1, -7).
