## ihavemathquestions 2 years ago Determine whether y varies directly with x. If so, find the constant of variation k and write the equation.

1. ihavemathquestions

2. agent0smith

You can either use the slope formula, $m = \frac{ y _{2}-y _{1} }{ x _{2}-x _{1} }$ or more simply, because it's only of the form y = mx, just divide each y term by it's x term, and check they all give the same value ie 24/6 = 72/18 = 216/54 = 648/162 = Check they all equal the same number.

3. ihavemathquestions

they all equal 4 @agent0smith

4. agent0smith

Which means each x is multiplied by 4 to get y, so the constant of variation is 4

5. ihavemathquestions

hmm. ok so how would i know which answer is right? yes; k = 4; y = 4x yes; k = 3; y = 3x yes; k = 6; y = 6x no

6. ihavemathquestions

i think that no is not the right answer @agent0smith

7. agent0smith

note that k is the constant of variation, and the constant of variation is 4 from what you worked out above.

8. ihavemathquestions

so A! @agent0smith

9. agent0smith

Correct :)

10. ihavemathquestions

thank you so much @agent0smith i really appreciate it <3

11. agent0smith

No prob :)