Answer:
y = - 24
Step-by-step explanation:
Given that y varies directly with x then the equation relating them is
y = kx ← k is the constant of variation
To find k use the condition y = 12 when x = - 3
k = =
= - 4
y = - 4x ← equation of variation
When x = 6, then
y = - 4 × 6 = - 24
The step function is characteristic of the floor or ceiling functions, which map a real number to an integer. There's clearly a factor of 2, indicated by two units of y for every one unit of x.
The open and filled circles indicate, for example, f(1)=2, f(1.01)=4. That means we're rounding up, so we're using the ceiling function.
Answer: second choice
