Question

HELP PLEASE !! Will mark brainiliest!

1. y varies jointly as x and z.

Answer 1

see explanation

Explanation:

since y varies jointly as x and z , then the equation connecting them is

y = kxz ← k is the constant of variation

to find k , use the row x = 5, y = 52.5, z = 7

k =
`(y)/(xz)` =
`(52.5)/(5(7))` = 1.5, hence

y = 1.5xz ← equation of variation

first row, to find y with x = 2, z = 4

y = 1.5 × 2 × 4 = 12

third row, to find z with x = 1.5, y = - 36

-36 = 1.5 × 1.5z

z =
`(-36)/(1.5(1.5))` = - 16

fourth row, to find x with y = 1.38, z = 23

1.38 = 1.5 × 23x

x =
`(1.38)/(1.5(23))` = 0.04