Question

finding slope using differences when given a table

Answer 1

Ok, what do you need help with?

Answer 2

it's basically the same question just double checking my work.

Answer 3

it is graduating students in millions given a number of years that increases by two

Answer 4

1985=2.83
1987=2.65
1989=2.47
1991=2.29

Answer 5

Ok so on the left side the change is 2 every time between each value.
On the right side you have a change of -0.8.

The key is to never start with your first values. Start at at least the second and subtract a pair of values before it.
You can even do 1991-1985 and 2.29-2.83!

Answer 6

ok but i think we shouldnt use the actual year but instead make 0 = first year right?

Answer 7

By all means, go right ahead. It doesn't matter though, because graphically it would look the same. I would encourage using whichever way feels most natural to you.

Answer 8

ok, what did you calculate the slope to be? if you did

Answer 9

It all depends on what you choose for y. I'm guessing students is y. So we would have -0.8/2 or -0.4 for the slope.

Answer 10

can i use the y2-y1/x2-x1?

Answer 11

Yeah, you sure can. Each row is a pair of values that makes up a point. So you can plug in the values and get the slope.

Answer 12

i keep getting -.09 as my slope??

Answer 13

you calculated the y wrong. it is a difference of .18 not .8

Answer 14

not to criticize im just saying the values

Answer 15

Yeah sorry, I must've just left out the one by accident, but its the same idea

Answer 16

no worries boss

Answer 17

now to find a formula

Answer 18

can i use the first year as the y intercept?

Answer 19

Yes! And this is where its easier if you think of 1985=0, 1987=2, and so forth like you suggested earlier.

Answer 20

SWEEEEET

Answer 21

now it asks for the number of graduating students in 1994 meaning 9 years after meaning y(x)=y(9)=2.02 million students??

Answer 22

Yeah, you got it, ace.

Answer 23

HECK YEAH

Answer 24

done. loved your no "problem" joke by the way lol thanks for all your help! byee

Answer 25

Alright! Hope everything is smooth sailing from here. See ya later!