Well basically if they lost 8 points and gained 6, they have -2 points.
You have to know that the graph of the arctangent function is a flat S-shaped curve that goes through (0, 0) and has asymptotes at ±π/2. The factor of 2 that multiplies it here expands it vertically so the asymptotes are at ±π. The +3 added to the x causes it to be shifted to the left by 3 units.
A mixed number is in the form x y/z while a improper fraction (76/10) is in the form y/z. We can separate the fraction into two parts. One is 70/10 which = 7 and the other is 6/10 which simplifies to 3/5. So, in order to express 76/10 as a mixed number we must express it as 7 3/5 or 7 6/10. 7 3/5 is equal to 7 6/10.
I hope this helped you!
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Answer and workings in the attachment below. Also, do me one big favour. Let me know if it's the answer your teacher or text book ends up giving you. That would give me some satisfaction.
Answer: 80%
P = A / (1 + rt)
P = 80000 / (1 + (0.09)(0.5))
P = <span>$ 76,555.02</span>