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?
No. Y is greater than x.
That's alright I got it
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
" 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
Tell whether the equation −4x + 2y = 5 represents a direct variation. If so, identify the constant of variation.
To determine the value of y when x=60, we can use the concept of direct variation. Direct variation means that as one variable increases, the other also increases proportionally. In this case, we can express the direct variation relationship as y = kx, where k is the constant of variation.
Given that y = 18 when x = 12, we can use this information to find the constant of variation, k.
y = kx
18 = k * 12
k = 18/12
k = 1.5
Now that we have the value of k, we can substitute it back into the equation to find y for the given value of x.
y = k * x
y = 1.5 * 60
y = 90
Therefore, the correct answer is y = 90, not 42.