<span>Inflection points are where the function changes concavity. Since concave up corresponds to a positive second derivative and concave down corresponds to a negative second derivative, then when the function changes from concave up to concave down (or vise versa) the second derivative must equal zero at that point. So the second derivative must equal zero to be an inflection point. But don't get excited yet. You have to make sure that the concavity actually changes at that point.</span>
Answer: at 50 mph, she drove for 4 hours.
at 45 mph, she drove for 2 hours.
Step-by-step explanation:
Let t represent the time that she spent driving at 50 miles per hour.
Taylor took 6 hours to drive home from college for Thanksgiving break. This means that the time that she spent driving at 45 miles per hour is (6 - t) hours.
Distance = speed × time
Distance covered while driving 50 miles per hour is
50t
Distance covered while driving 45 miles per hour is
45(6 - t)
Since the total distance that she drove is 290 miles, it means that
50t + 45(6 - t) = 290
50t + 270 - 45t = 290
50t - 45t = 290 - 270
5t = 20
t = 20/5 = 4
At 45 miles per hour, she drove at
6 - 4 = 2 hours
Answer:
B. x < -1
Step-by-step explanation:
Hello!
Let's put them in order from greatest to least:
Given our possible inequalities, we need to find the inequality that contains all of these values.
The inequality that works is x < -1, as <u>all values are less than -1.</u>
Therefore, the answer is B. x < -1.
(3x³ - 7x² + 12) - (3x³ + 6x² + 10x)
(3x³ - 3x³) + (-7x² + 6x²) - 10x + 12
-x² - 10x + 12
