To find th vertex use the formula -b/2(a) so it's -8/2(1) so it's -4. Plug in the -4 into the original equation -4^2+8(-4)+3
16-32+3
-13
The vertex is (-4,-13)
It's minimum because the first coefficient is positive which means the parabola open up like a giant U and when plotted the vertex is a negative.
Use cosine rule:-
b^2 = 41^2 + 20^2 - 2*20*41*cos 36
= 754.21
b = 27.5
you can now find angle A using the sine rule
27.5 / sin 36 = 41 / sin A
sin A = 0.87633
< A = 61.2 degrees
His average speed for the entire trip is 46.6 mph
We have,
30 miles at 40 mph
time taken at this speed = 30/40 = 3/4 hours
..
75 miles at 50mph
time taken = 75/50 = 3/2 hours
Total time taken = 3/4 +3/2 hours=3+6 /4
=9/4 hours
Total distance traveled = 30+75 = 105 miles
Average speed = 105/ 9/4
=105*4/9
46.6 mph is the average speed.
Learn more about average Speed:
brainly.com/question/11753352
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Answer:
I believe it is B
Step-by-step explanation:
Social media reaches a lot of people
Answer:
9
Step-by-step explanation:
3/4=12
