Question

2. Find y when x = 1.5, if y varies
directly as x and y = -16 when
6.

Answer 1

-4

Explanation:

We know that the general way directly proportional equations are formed is y = k × x where 'k' is the constant so let's start substituting in the values,

y = k × x

→ The first step would be to substitute in y = -16 when x = 6 so then we can find the 'constant'

-16 = k × 6

→ Divide both sides by 6 to isolate k

`-(8)/(3)` = k

Now we know the value of k we can substitute x = 1.5 in the equation with 'k' as
`-(8)/(3)` so

y =
`-(8)/(3)` × x

→ Substitute in 'x'

`y =- (8)/(3) *1.5`

→ Simplify

y = -4

Find y when x = 1.5, if y varies directly as x and y = -16 when x = 6. The value of y when x = 1.5 is -4