Question

The values of x and y vary directly and one pair of values are given. Write an equation that relates x and y. Simplify completely.

x=-5,y=10
Please need help badly!!

Answer 1

y = - 2x

Explanation:

Given that x and y vary directly then the equation relating them is

y = kx ← k is the constant of variation

To find k use the condition x = - 5, y = 10

k =
`(y)/(x)` =
`(10)/(-5)` = - 2

y = - 2x ← equation of variation