Question

LINEAR FUNCTION HELP
For a certain linear function, y = 17 when x = 8, and y = 26 when x = 11. What is the initial value of that function?

Answer 1

So you know that f(8) = 17 and f(11) = 26.
You can write linear functions like y-y1 = m(x-x1)
So your first step should be to calculate m (the slope)

Answer 2

When you get the slope, you just use one pair of coordinates and get the answer in the general form y= mx + b

Answer 3

ok i got 3 as the slope. is that correct ?

Answer 4

Yes :)

Answer 5

so can i set it up like 17=3(8)+b ?

Answer 6

Work with this first y-y1 = m(x-x1)

Answer 7

What do you get from this? (Use the one you want)

Answer 8

im not sure if I'm doing this correct of not .... i got -9=3(-3)+b

Answer 9

Nope...You can't substitute into y and x because those changing. You can substitute the values of a point P(x1,y1)

Answer 10

So if you know that the slope is 10 and you know that the lines passes through (8,9), you can do:
y-9= 10(x-8)
y = 10x - 80 + 9
y = 10x -71

Answer 11

oh ok so i don't plug them in for x and y, just how u have it here next to them

Answer 12

y=3x-7 hows that ?

Answer 13

Yes. Think about the problem per se. You know that the values of x and y will be changing all the time. But you know the slope and a point, so you can draw all the function with that.

Answer 14

It is correct

Answer 15

ok thank you so much i got it from here, thanks for your help i totally understand now

Answer 16

Good. You should still try to solve one more