Tamara J. answered • 02/16/13

Math Tutoring - Algebra and Calculus (all levels)

A linear equation in slope-intercept form is given by the following formula:

y = mx + b ,

where 'm' is the slope of the line and 'b' is the y-intercept of the line (i.e., the point on the graph where the line intersects with the y-axis, or the point on the line where x= 0).

You are given that the line in question passes through the point (0, 1) and has a slope of -9. That is, we are given the following information:

(x, y) = (0, 1) ==> x = 0 , y = 1

slope = m = -9

Using the slope-intercept formula, we plug in these numbers and solve for the y-intercept (b):

y = mx + b

1 = (-9)·(0) + b

1 = 0 + b

1 = b

We can now state the equation of this line in slope-intercept form using its given slope (m = -9) and its y-intercept (b = 1), which we just solved for:

y = mx + b

y = -9x + 1