Question

Suppose x varies directly with y

Answer 1

what's the equation for direct variation ??

Answer 2

Huh?

Answer 3

What do you mean

Answer 4

i mean how would you write an equation for direct variation ??the general equation

Answer 5

i really dont know

Answer 6

I'm terrible at this

Answer 7

`y=kx` equation for direct variation
where `k` is constant of variation.

Answer 8

Yes setup a constant ratio, as they say x and y are directly related to one another

Answer 9

now read first part) given is x and y values plug that into the equation
and then solve for `k`

Answer 10

i dont know what any of this means, its kind of just practice. it works better if i see the steps laid out

Answer 11

alright for part `a` use the fact that x = 45 when y = 80 to find the constant of variation and write the equation
now substitute x and y for given values
\[\large\rm \color{ReD}{y}=k\color{blue}{x}\]
replace x with 45 and y with 80
\[\large\rm \color{ReD}{80}=k\color{blue}{(45)}\]
now in order to solve for k divide both sides by 45
\[\rm \frac{80}{45}=k\]

Answer 12

Do i divide it?

Answer 13

now i'll just reduce the fraction by dividing both top and bottom by 5

Answer 14

divide k by 45?

Answer 15

now your goal is to solve for k.
so that's why we should move x value ( which is 45 ) to the opposite side

Answer 16

no* not now

Answer 17

\[\large\rm y=kx\] to solve for k you should divide x both sides ( our goal is to get rid of the x ) from right side

Answer 18

so what do i do to get rid of it?

Answer 19

so 80=k(45) you should divide both sides by 45