Question

Tell whether x and y show direct variation, inverse variation, or neither.

1. y=2x+3
2. y=x/3
3. x=3/y
4. 1/2xy=2

Answer 1

@Mertsj

Answer 2

find some ordered pairs. If the variation is direct, y/x will always be the same number
If the variation is inverse xy will always be the same number
Otherwise, it is neither

Answer 3

Let us look at number 1. (1,5) (2,7) (3,9)
5/1=5
7/2=3.5
Nope. Not direct
1x5=5
2x7=14
Nope. Not inverse
Neither

Answer 4

can u do it another way? our teacher never said anything about ordered pairs....like he said to rewrite the equation?

Answer 5

I have no way of knowing what your teacher said. You should consult your notes.
If the equation can be written y = kx it is direct variation
If the equation can be written y = k/x, it is inverse variation
Otherwise it is neither.

Answer 6

how about number two? is it inverse?

Answer 7

@Mertsj

Answer 8

for # three i got direct and for # 4 inverse?

Answer 9

@Mertsj

Answer 10

You said number 2 is inverse. Is it of the form y = k/x?

Answer 11

no its x/k

Answer 12

wait what is k??

Answer 13

A constant.

Answer 14

so its neither for #2?

Answer 15

y=x/3 is the same as y =(1/3)x

Answer 16

direct

Answer 17

can u check #3 and 4?

Answer 18

3. x=3/y
Multiply both sides by y. What do you get?

Answer 19

y=3/x

Answer 20

inverse

Answer 21

yes.
What about 4?

Answer 22

inverse

Answer 23

yes