Question

The value of y vaires directly with x, and y=18 when x=12. Find y when x=60.

y=90
y=42****
y=1.5
y=40

Am I right?

Answer 1

No. Y is greater than x.

Answer 2

That's alright I got it

Answer 3

The value of y vaires directly with x mean:

y and x always have the same ratio k.

k = y / x

In ths case:

k = y / x = 18 / 12 = 6 ∙ 3 / 6 ∙ 2 = 3 / 2 = 1.5


k = y / x

y = k x

When x = 60

y = 1.5 ∙ 60 = 90

Answer 4

" y varies directly with x" -----> y = kx, k is a constant

given: y=18 when x=12
18 = 12k
k = 3/2

so you have y = (3/2)x
when x = 60 , y = (3/2)(60) = 90

Answer 5

Tell whether the equation −4x + 2y = 5 represents a direct variation. If so, identify the constant of variation.