<span>P = (6,31°) is already a polar coordinate.
In the notation (r, </span>α) if you make r negative, it points in the opposite direction. If you add 180° to α you compensate for that.
Therefore (6,31°) = (-6,31°+180°) = (-6, 211°)
However, it is more usual to keep r positive.
Answer:
E started with 26 books, sold 13 books, bought 17 more books, and ended with 30 books
Step-by-step explanation:
E has _ books: x
E Sells 1/2 of that _ books: x/2
E buys 17 books and now had 30: (x/2) + 17 = 30
30 - 17 = 13
13 x 2 = 26
x/2 = 26
13 + 17 = 30 <-- checking work
My guess is that x = 13
You didn't clarify what exactly you are looking for but I hope this helps clarify some steps of the problem anyway!
Answer:
8:30 PM
Step-by-step explanation:
Let's say that x is minutes since 6:20 PM, and y is position in miles.
Since Jonathan drives at a constant rate, the position vs time graph is linear. Two points on the line are (0, 75) and (20, 85). The slope of the line is:
m = Δy / Δx
m = (85 − 75) / (20 − 0)
m = ½
So the equation of the line is:
y = ½ x + 75
We want to find x when y is 140.
140 = ½ x + 75
65 = ½ x
x = 130
So 130 minutes after 6:20 PM is when Jonathan's position will be 140 miles. 130 minutes is 2 hours and 10 minutes. So the time will be 8:30 PM.
