Question

What is the equation of the line that passes through the points (-1, 3) and (1, 11)?

4x - y = 1

4x + y = 1

x - 4y = -13

4x - y = -7

Answer 1

Use y = mx + b:

3 = -m + b
11 = m + b

Combine the equations together to get

14 = 2b

Divide both sides by 2 to get
7 = b

Substitute b back into the original equation to get m:

11 = m + 7
11 - 7 = m
4 = m

Therefore the equation of the line is

y = 4x + 7

Answer 2

Well I'll help you out, basically we have have the formula y=mx+b.

m is the slope of the line and b is our y-intercept. So to best figure this out, take your graphing calculator and look at lines of y=x, y=2x, and y=(1/2)x. Play around and discover why slope is described as \[\frac{ rise }{ run }\]

Answer 3

or you can manipulate that to get 4x - y = -7

Answer 4

What happens when x is 0? Then y=mx+b just sets y=b. So this is why it's called the y-intercept, since at x=0 you're on the y-axis.