The value of y directly varies with x, and y=5.4 when x =9. Find y when x= negative 10

Mathematics · High School · Thu Feb 04 2021

Answered on

Given the statement:

The value of y directly varies with x, and y=5.4 when x =9.

Find y when  x = -10

Solution:

In order to find y, we must first determine the constant of variation, which can be solved by multiplying x and y.

k = xy

k = (5.4)(9)

k = 48.6

To find for y, we substitute the values of x and k to the constant of variation formula.

48.6 = (-10)(y)

Solve for y.
Divide -10 on both sides of the equation, this cancels out -10y, leaving behind y.

48.6 = -10y 

48.6/-10 = -10y/-10

y = -4.86

Final answer:

y = -4.86