Question

Can someone help me understand this.

Determine the coordinates of the y-intercept of the function shown in the graph.
A)
(-6, 0)
B)
(-2, 0)
C)
(0, -2)
D)
(0, -6)

Answer 1

do you know how to find the equation of a line with 2 points given ?

Answer 2

I know that the y-intercept is where the line intersects the y-axis.

Answer 3

correct, but to get it we have to find the equation of the line in slope-intercept form

which is in general like this y = mx + b

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

Answer 4

So would i find for both points or would i have to choose which point?

Answer 5

you have to use both points to find the equation
you have to find the slope first

do you know how to do that ?

Answer 6

I think, please correct me if I'm wrong:

So for the top point, would it be y=-4x+6
and the second point, y=-3x+3

Answer 7

the equation is for the line passing by the two points, so we will have just one equation

Answer 8

ok so would i set them equal to each other?

Answer 9

do you know what is the slope ?

Answer 10

Not really

Answer 11

Oh wait is it -1/3

Answer 12

\[m = \frac{ y_2 - y_1 }{ x_2-x_1 }\]

Answer 13

it's not -1/3

Answer 14

ok . . . so is m=-3

Answer 15

Sorry wait i take alot of that back so the y=mx+b: y = -3x - 6.

Answer 16

correct!
so what's the y-intercept ?

Answer 17

-6.

Answer 18

correct

Answer 19

Ooohh! so it D. Thanks so much

Answer 20

yeah it's D
glad to help :)