Question

I need help. Can you write a rule for the linear function in the graph?


A. y = -4x + 13
B. y = -4x – 13
C. y = 4x – 13
D. y = 1/4x – 13

Answer 1

@Nnesha ?

Answer 2

Is there a graph that goes with the first question?

Answer 3

Sorry @aum, here is the graph.

Answer 4

I uploaded the graph, @aum

Answer 5

they give you two points on the line (3,-1) and (4,3)

do you know how to find the slope between those points?

Answer 6

no, sorry =(

Answer 7

do you know that they are (x,y) pairs?
can you pick out the y values for those two points ?

Answer 8

3 and -1???

Answer 9

yes. the first step is find the "change in y" which means subtract
can you do that ?

Answer 10

Subtract 3 and -1?

Answer 11

yes

Answer 12

4?

Answer 13

3 - -1 = 3+1 = 4
yes
now find the x values of the two points and find the "change in x"

Answer 14

4-3=1?

Answer 15

Sorry the notifications don't work too well. Just got the notification 25 minutes later.

Answer 16

yes

finally, slope is change in y divided by change in x

Answer 17

lol its okay @aum =)

Answer 18

0.25?

Answer 19

what did you get for change in y ?

Answer 20

4

Answer 21

and 1 for change in x

now do "change in y" over "change in x"

Answer 22

4/1

Answer 23

and that simplifies to just 4

Answer 24

you found the slope is 4

now we use
y = m x + b

that is the formula of a line. m is the slope. We could use the info to also find b.
but so far, we know this:
y= 4 x + b

so your choice better have a 4x in it.

Answer 25

okay cool!

Answer 26

only 1 choice works. but if we wanted to find the "b" in
y = 4 x + b
use one of the points, say (3,-1) which says when x is 3, y is -1. use those in the equation:
-1 = 4*3 + b
4*3 is 12
-1 = 12 + b
now add -12 to both sides
-1 - 12 = 12 - 12 + b
simplify to get
-13 = b

and the full equation is
y = 4x -13

Answer 27

WOW! Thank you for your brain! =)