Question

1. Direct variation

A. Write an equation for the following statements.
B. Write an equation when y varies directly as x.
1. y=63 when x=9
2. y=121 when x=11
3. y=36 when x=4
4. y=224 when x=8

Answer 1

(1) y = 7x , (2) y = 11x , (3) y = 9x , (4) y = 28x

given y varies directly as x then y = kx ( k is the constant of variation )

(1) find k using the given conditions k =
`(y)/(x)` =
`(63)/(9)` = 7

equation is y = 7x

(2) k =
`(121)/(11)` = 11

equation is y = 11x

(3) k =
`(36)/(4)` = 9

equation is y = 9x

(4) k =
`(224)/(8)` = 28

equation is y = 28x