Question

Use function notation to write the equation of the line.

bit.ly/1ffoCNs

A.


f (x) = 2x – 1


B.


f (x) = –2x – 1


C.


f (x) = –½x – 1


D.


f (x) = –2x + 1

Answer 1

@UnkleRhaukus

Answer 2

f(x)=mx+b

where m is the slope, and b is the y-intercept

Answer 3

But, I dont even know what to plug into the unknown variables

Answer 4

look at the plot, what value does the line cross the y-axis?
this is the y-intercept b

Answer 5

(0,-1)?

Answer 6

So b=-1?

Answer 7

yes

Answer 8

f(x)=mx+(-1)

Answer 9

that is the y-intercept so your almost there

Answer 10

now you just need to get the slope (or gradient )

Answer 11

the gradient is the amount the height changes , when the vertical displacement is positive one unit

Answer 12

or equivalently slope is rise/run between any two points

Answer 13

i like to choose a run of +1 to make it easy

Answer 14

Ok

Answer 15

m = rise/run = (y_2-y_1)/(x_2-x_1)

choose two points, say (x_1, y_1) = (0,-1)
and say (x_2, y_2) = (1, -3)

(if you want to you can choose any two points)

Answer 16

Ok, I will just use the points you used

Answer 17

Y=2
X=-1?