Answer:
Joint variation says that:
if
and 
then the equation is in the form of:
, where, k is the constant of variation.
As per the statement:
If x varies jointly as y and z
then by definition we have;
......[1]
Solve for k;
when x = 8 , y=4 and z=9
then
Substitute these in [1] we have;

⇒
Divide both sides by 36 we have;

Simplify:

⇒
to find z when x = 16 and y = 6
Substitute these value we have;

⇒
Multiply both sides by 9 we have;

Divide both sides by 12 we have;
12 = z
or
z = 12
Therefore, the value of z is, 12
Answer:
The Answer is b. 1.5Million
Step-by-step explanation:
Adult Population = 50 Million
Labor-Force Rate = 60%
Total Labor Force of Adult population = 50Million*60% = 30Million
Unemployment Rate = 5%
People Unemployment =
Total Labor force of Adult population * Unemployment rate
People Unemployment = 30Millon*5%
People Unemployment = 1.5Million
Answer:

Step-by-step explanation:

Answer: Chun is incorrect. He made a mistake in step 2.
Step-by-step explanation:
Answer:
the slope of the common cord is: 
Step-by-step explanation:
Given the focus (a,b) = (3,-28)
- for a parabola with directrix at x-axis the equation will be


- for a parabola with directrix at y-axis the equation will be


The common chord is the line between two points where the two parabolas intersect. For intersection, we can equate the two parabolas!
In other words, at the point of intersection of these two parabolas the values of the two parabolas will be the same.


we can now simplify the equation. (we can see that (x-3) and (y+28) both cancel out by -(x-3) and -(y+28))



this the equation of the common cord. but we need to select whether its
or
.
This can be found by realizing that the focus lies on the 4th quadrant of the xy-plane! And the equation
also generates a line that exists in the 2nd and 4th quadrant.
Hence the slope of the common cord is the slope of the line 
that is :