Answer:
It's a, 4
Step-by-step explanation:
First, we find the time spent accelerating:
s = ut + 1/2 at²; u = 0
10 = 1/2 5t²
t = 2 seconds
Velocity at point B:
v = u + at; u = 0, a = 5 m/s², t = 2 s
v = (5)(2) = 10 m/s
Now, the same velocity is at C so we find the time decelerating to 0 in CD
v = u + at, v = 0, u = 10 m/s, a = -4 m/s²
0 = 10 - 4t
t = 2.5 seconds
Total time = time(AB) + time(BC) + time(CD)
20 = 2 + time(BC) + 2.5
time(BC) = 15.5 seconds
Distance = velocity x time
BC = 10 x 15.5
= 155 m
The solution to the equation by completing the square is (6 - √21, 6 + √21)
<h3>How to complete the square?</h3>
The equation is given as:
x²= 12x-15
Rewrite as:
x² -12x = -15
Take the coefficient of x
k = -12
Divide by 2
k/2 = -6
Square both sides
k/4 = 36
Add 36 to both sides of x² -12x = -15
x² -12x + 36 = -15 + 36
Evaluate the sum
x² -12x + 36 = 21
Express the equation as a perfect square
(x - 6)² = 21
Take the square root of both sides
x - 6 = ±√21
Add 6 to both sides
x = 6 ± √21
Split
x = (6 - √21, 6 + √21)
Hence, the solution to the equation by completing the square is (6 - √21, 6 + √21)
Read more about solution set at:
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4 slices
There are 5 pizzas, with 8 slices each. That means there are 5 x 8 = 40 total slices of pizza. Since there are 10 students, dividing the slices evenly between students means that each student gets 40/10 = 4 slices