Hello!
If y varies jointly with x and z, it'll mean that x and z are being multiplied by a factor "k", to equal y.
To give you a visual, this is what I mean.
That means we'll want to find 
with the first point we're given: 
Which means our equation is:
Now, let's plug in the 
and 
from the other point to find 
.
Hope this helps!
Answer:
After 5 years of investment, Suzanne will have $ 4,400 in her account, while Derek will have $ 4,416.32 in his account.
Step-by-step explanation:
Since Suzanne deposits $ 4000 in an account that earns simple interest at an annual rate of 2%, and Derek deposits $ 4000 in an account that earns compound interest at an annual rate of 2% and is compounded annually., Both for a period of 5 years, to determine how much money each one will have in their account after 5 years, the following calculation must be made:
Suzanne:
((4,000 x 0.02) x 5) + 4,000 = X
(80 x 5) + 4,000 = X
400 + 4,000 = X
4,400 = X
Derek:
4,000 x (1 + 0.02 / 1) ^ 5x1 = X
4,000 x 1.02 ^ 5 = X
4,416.32 = X
Thus, after 5 years of investment, Suzanne will have $ 4,400 in her account, while Derek will have $ 4,416.32 in her account.
You need to substitute the y for 32 and multiply the -5 by the -7. I got 32=37.
