Step-by-step explanation:
1. The equation graph is a parabola, so the maximum height will be the vertex of the parabola. You can find the vertex coordinate t using the formula:
t = -b/2a
t = -18/2•(-4.9)
t = -18/-9.8
t = 1.84 seconds
2. The height of the ground is 0, so the balls hit the ground when the equation result is 0:
0 = -4.9t²+18t+10
Now you solve it using Bhaskara:
Δ = b² -4ac
Δ = 18² -4•(-4.9)•10
Δ = 520
t = (-b ±√Δ)/2a
t = (-18 ± √520)/2•(-4.9)
t1 = (-18 - 20.8)/-9.8
t1 = 3.96 seconds
t2 = (-18 +20.8)/-9.8
t2 = -0.28
Doesn't exist negative time, so we pick the first value found, t = 3.96 seconds
3. Now you just need to put 3 in place of t to find the result:
h = -4.9•3² +18•3 +10
h = -4.9•9 + 54 + 10
h = -44.1 + 64
h = 19.9 meters
4. You just need to put 1 in place of t to find the height:
h = -4.9•1²+12
h = -4.9+12
h = 7.1 meters
Answer: The total number of logs in the pile is 6.
Step-by-step explanation: Given that a stack of logs has 32 logs on the bottom layer. Each subsequent layer has 6 fewer logs than the previous layer and the top layer has two logs.
We are to find the total number of logs in the pile.
Let n represents the total number of logs in the pile.
Since each subsequent layer has 6 fewer logs then the previous layer, so the number of logs in each layer will become an ARITHMETIC sequence with
first term, a = 32 and common difference, d = -6.
We know that
the n-th term of an arithmetic sequence with first term a and common difference d is

Since there are n logs in the pile, so we get

Thus, the total number of logs in the pile is 6.
I got 5 inches b/c 8-5 1/4 equals to 2 3/4. 2 3/4 is equal to two feet and 9 inches. 28 inches is equal to two feet and four inches. Nine inches minus four inches equals five inches.
- 4(20+22)
- 4(40+2)
This expression are equivalent to 4(42)