Question

Help Would Be Greatly Appreciated :)

What is the graph of the line if m and b are both 0?

Can you write the equation of a vertical line using slope-intercept form?

Margo used the equation y = −4x − 1 to graph a line. She graphed the point (−1,0). Does (−1,0) lie on the line? What mistake did Margo make?

Answer 1

if the slope "m" and the y-intercept "b" are both 0, then the slope-intercept form of it could just be written as

y = 0x + 0

which of course is just y = 0.

now, is (-1,0) on the line y = -4x -1?

well, to find the other coordinate, we can simply plug in the known coordinate value, say hmmm if we set x = -1, do we get 0 for "y"? let's check

y = -4(-1) - 1

y = 3.................................. for the point (-1, 3)

whatever happened to Margo? well, we gather she used x = 0, y = -4(0) - 1, y = -1, and that gives the point (0, -1) NOT (-1, 0).

so her mistake is, she used the y-coordinate value of 0 and used it on the "x" value to get the -1.l

however (-1, 0) is not on the line, but (0, -1) is.