The variables x and y vary directly. use the values to find the constant of proportionality, k. then write an equation that relates x and y. write any fractions in simplest form. y=20; x=12

Vary Directly: x = k*y

Vary Inversely:  x = k/y

Because x and y vary directly, our equation will look like the first one.

x = k*y

With the inputted values:

12 = k * 20

Now, to find k, isolate the variable

Therefore,

k = 12/20 = 3/5 = 0.6

Your final equation will then look like this:

x = 3/5 * y      or       x = 0.6 * y

option 3 . (5x + 1) - (-10x + 6)

step-by-step explanation:

option 1 :

(4x + 3) + (-9x + 4)

or 4x+3 -9x + 4

or -5x + 7

option 2

(x - 2) - (6x - 9)

or x-2-6x + 9

or -5x + 7

option 3

(5x+ + 6)

or 5x + 1 + 10x -6

or 15x -5

option 4

-4x+2x+7-3x

-7x + 2x + 7

-5x + 7

hence only option 3 did   not satisfy the given simplify expression.