Question

Every time x increases by 1,y decreases by 3,and when x is -6,yis-3.which function models the realation ship between x and y?

A)y= -6x-21
B)y= -6x-3
C)y= -3x-3
D)y= -3x-21

Answer 1

I think that it would be B because -6x-3 seems to follow the rules given here.

Answer 2

D.
`y=-3x-21`

Explanation:

We have been given that every time x increases by 1,y decreases by 3. This means that slope of our given line is negative 3.

We will use slope-intercept form of equation to find the required function.

`y=mx+b`, where,

m = Slope of line,

b= The y-intercept.

Upon substituting
`m=-3` and
`x=-6` and
`y=-3` in slope-intercept form of equation, we will get,

`-3=-3* -6+b`

`-3=18+b`

`-3-18=18-18+b`

`-21=b`

Upon substituting
`m=-3` and
`b=-21` in slope-intercept form of equation, we will get our required equation as:

`y=-3x-21`

Therefore, option D is the correct choice.