Question

Which equation has a constant of proportionality equal to 4?
a . 4y= 4x
b. 4y = 12x
c. 3y = 4x
d. 3y= 12x
How do I figure out which is correct?

Answer 1

d. You want "k" in y = kx to be 4. So, in 3y = 12x if you divide both sides by 3 you get y = 4x.

Answer 2

How do I know to mult. by 3?

Answer 3

You don't multiply by 3. You divide by 3 to get y by itself.

Answer 4

How do I know to divide by 3?

Answer 5

Because that's how you get "y" by itself. You want to get "y" by itself because the equation is y = kx.

Answer 6

Still do not understand, what if I used 4?

Answer 7

Which one? If you used a. "4y = 4x" and you solved for "y" you would get y = x. The coefficient of "x" is then 1, so k does not equal 4, it equals 1.

Answer 8

If you used b. "4y = 12x" and solved for y you would get y = 3x. "k" is then equal to 3, not 4.

Answer 9

So I would just try different numbers to see which number would divide into the number evenly with the number 4 given

Answer 10

Whenever the equation is "y = 4x" then your constant of proportionality is always 4. There's only 1 answer. You were just given a list of multiple choice, so you had to find which one had "k" as 4.

Answer 11

I think I understand now. Thank you so much!

Answer 12

Yeah, no problem!