Question

Which functions have a positive rate of change and which have a negative rate of change?
Column A Column B
1.
2x + 3y = −9

2.
y = 3x − 6


3.
x y
−1 9
0 7
1 5



4.
x y
2 −8
3 −7
4 −6

Answer 1

Are these functions positive or negative?

Answer 2

@DanJS

Answer 3

rate of change is also known as , slope of the line , change in y coordinate vs a change in x coordinate

Answer 4

2x + 3y = −9

rearrange it , to y= m*x + b look at the sign on m, + or - rate of change

Answer 5

So negative?

Answer 6

right

Answer 7

The second one is already in form y = m*x+b
look at the sign on m

Answer 8

Ok so 2 is positive?

Answer 9

yes, rate of change 3 y values per 1 x value

Answer 10

Ok now how do i solve the charts?

Answer 11

The next 2, they give you points on the line
(x,y) and (x1,y1)
calculate

m = (y-y1) / (x-x1) that is the slope (rate of change )

Answer 12

Ok i think i get it

Answer 13

For 3) you can use 2 points
(-1 , 9)
(0 , 7)

calculate difference in Y coordinates over difference in X coordinates

Answer 14

So it would be positive?

Answer 15

And 4 would be negative?

Answer 16

rate of change = (7 - 9) / (0 -(-1)) = -2 / 1 = -2

Answer 17

Oh so opposite?

Answer 18

3 is positive and 4 is negative?

Answer 19

I mean negative

Answer 20

And 4 is positive lol sorry

Answer 21

For 3) 2 points (-1 , 9) and (0,7)

\[m = \frac{ y - y1 }{ x - x1 } = \frac{ 7 - 9 }{ 0 - (-1) } = \frac{ -2 }{ 1 } = -2\]

negative rate of change

Answer 22

do the same thing for 4

Answer 23

Ok

Answer 24

I got a positive 1 for 4 is that right??