Question

Every time x increases by 1, y decreases by 3, and when x is -6, y is -3. Which function models the relationship between x and y?
a) y= -6x - 21
b) y= -6x - 3
c) y= -3x - 3
d) y= -3x - 21

Answer 1

It's b right ?

Answer 2

Every time x increases by 1, y decreases by 3 --> this tells you something about the slope, because the slope is [change of y]/[change of x]

when x is -6, y is -3 ---> this together with the slope allows you to figure out the starting position (the '+b' part. as in y=ax+b)

Answer 3

so, based on that, what do you think the slope is, to start with?

Answer 4

-3?

Answer 5

i mean -6

Answer 6

yeah -6

Answer 7

Every time x increases by 1, y decreases by 3

Answer 8

so \[slope = \frac{ \Delta y }{ \Delta x } = \frac{ -3 }{ 1 }\]

Answer 9

oh okay

Answer 10

im still lost here does the -6 and -3 have to plugged in ?

Answer 11

y=ax+b where a is the slope.
you know the coordinates x=-6 and y=-3
-3 = -3 (-6) + b

solve b and you'll know the answer

Answer 12

So the answer is c?

Answer 13

i think you missed a sign somewhere

Answer 14

I think im doing it wrong