Y is directly proportional to x
If y= 10 when x=-5 what is the value of y when x =30. The answer should be a number.
"Y is directly proportional to x" ---> y = kx, where k is a constant
you are given x=-5, y = 10
so
10 = k(-5)
k = -2
then y = -2x
so when x = 30
y = -2(30) = -60
Thanks. i got -60 the first time, but when i was checking it I was getting -6 so I'll have to see what i was doing wrong! Thanks!!
Y=30 when x=6 what is value of y when x=5
To find the value of y when x = 30, we can use the concept of direct proportionality. Since it is stated that "Y is directly proportional to x," it means that as x increases or decreases, y will also increase or decrease in proportion to x.
In direct proportionality, we can use the formula:
y = kx
Where y is the dependent variable, x is the independent variable, and k is the constant of proportionality.
To solve for the constant of proportionality, k, we can use the given data point: when x = -5, y = 10.
Substituting these values into the formula, we have:
10 = k(-5)
Simplifying the equation, we get:
-5k = 10
Divide both sides of the equation by -5 to solve for k:
k = -2
Now that we know the constant of proportionality, we can substitute it back into the formula to solve for y when x = 30:
y = (-2)(30)
Simplifying the equation, we find:
y = -60
Therefore, the value of y when x = 30 is -60.