Macro can finish the puzzle in 3 hours. We can say that her speed for working is 1/3 or 1/3 puzzle per hour.
Now if they work together, this turns into 1 puzzle per hour.
That must mean that Cliff would be doing the other 2/3 of the puzzle while Macro does his 1/3 in that hour. If Cliff has a speed of doing them 2/3 per hour. Then it would take 1 and a half hour to finish 1 whole puzzle.
The expected value is $8,000.
Consider number 17. You know that
17=9+8.
Then for negative numbers you have the same rule (with respect to sign -):
-17=(-9)+(-8).
Since (-9)+9=9+(-9)=9-9=0, you have that
-17+9=(-9)+(-8)+9=(-9+9)+(-8)=0+(-8)=-8.
Answer: -17=(-9)+(-8).
F(x) = x^2 - 3x - 8
f(-2) = (-2)^2 - 3 (-2) - 8
f(-2) = 4 - 3 (-2) - 8
f(-2) = 4 + 6 - 8
f(-2) = 10 - 8
f(-2) = 2 ✅
22/25 i believe... i hope this helps