Direct/Inverse Variation

NO SPAM ALLOWED! Discuss stuff not related to Japan or Japanese. The rules are the same in this forum as in the other forums.
Post Reply
Posts: 62
Joined: Thu 11.15.2007 5:23 pm

Direct/Inverse Variation

Post by kevinnwhat » Thu 03.06.2008 8:09 pm

hello everyone, im sorry but i didnt really have any forum to put this one, so i thought i would give it a shot here. I cant get in touch with any of my friends so thats why im posting here.
Basically, i was absent when my teacher taught this lesson, and now i have a quiz on it, and i have no clue what im doing. Its on direct/indirect Variation. For the problem,

Y Varies Directly as X. If y = 14 when x = 2, find y when x = 5.

Is it set up as, k = y/x. K is your constant. So its k = 14/2 --> k = 7. Is this right? then you multiply it by 5? answer = 35?

when its inverse, is it the same thing but k = y * x (y times x)

im really confused, if anyone can help me with this i would really really really appreciate it.

User avatar
Posts: 3577
Joined: Tue 07.11.2006 10:48 pm
Native language: English (Australian)
Gender: Male
Location: Australia (SA)

Re: Direct/Inverse Variation

Post by chikara » Thu 03.06.2008 8:32 pm

If it is direct variation y = kx so to find k you divide both sides by x, k = y/x as you have said.

y = 14, x = 2, k = ?
k = y/x = 14/2 = 7

Find y when x = 5
y = kx = 7 * 5 = 35

I agree with your solution :)

When it is inverse it is not "the same thing" but y = k/x so to find k multiply both sides by x, k = yx as you have said ;)
Don't complain to me that people kick you when you're down. It's your own fault for lying there

Posts: 6
Joined: Wed 03.05.2008 3:38 am

Re: Direct/Inverse Variation

Post by kudamono-chan » Sun 03.16.2008 1:03 am

That was the one topic I really had trouble with on my Algebra 1 final...I ended up writing it on the one notecard we were allowed to have :oops:

Post Reply