Hello,
f(1)=160
f(2)=160*(-2)
f(3)=160*(-2)²
f(4)=160*(-2)^3=-1280
f(n)=160*(-2)^(n-1)
You add each number to get the next number and you find that the answer is 146:D
The drain pipe can drain (1/2) of the tank in 1 hour.
The fill pipe can fill (1/6) of the tank in 1 hour.
Working together, the pipes will drain the tank in (1/2) - (1/6) hours.
(1/2) - (1/6) = (3/6) -(1/6) = (2/6) or (1/3) of an hour.
So, working together, it will take 3 hours.
17=z-(-9)
17=z+9
17-9=z
8=z To check
17= 8-(-9)
17= 8 +9
17=17 it checks
