Question

what is the equation of direct variation, given that y varies directly with x.

y is 15 when x is 30

Answer 1

"y varies directly with x" MEANS y = kx. Just write it down when you hear it..

Answer 2

y = kx

15 = k*30 ... plug in x = 30 and y = 15

solve for k and tell me what you get

Answer 3

are you able to find k at all?

Answer 4

15+30=-15 ?

Answer 5

k*30 means k times 30

Answer 6

how do you undo multiplication?

Answer 7

30-15=15

Answer 8

division is the opposite of multiplication, agreed?

Answer 9

oohhhh 30 /15=2

Answer 10

close

Answer 11

but you flipped them around

Answer 12

0.5

Answer 13

or 1/2

Answer 14

so k = 1/2

Answer 15

and here's the full step by step picture


y = kx


15 = k*30


15/30 = k*30/30


15/30 = k*1


1/2 = k


k = 1/2


-----------------------------------------


\[\Large y = kx\]


\[\Large y = \frac{1}{2}x\]


-----------------------------------------


So the answer is


\[\Large y = \frac{1}{2}x\]

Answer 16

okay thanks i get it alot better now!(:

Answer 17

that's great, glad it's all clicking now, yw

Answer 18

@jim_thompson5910 strikes again lol
By the way he is one of the best teachers :)

Answer 19

lol im a slow thinker that all!

Answer 20

no worries, you don't have to rush anything

if you go too fast, then you won't learn the best you can

Answer 21

true!