Answer:
They are at the same height at 1.13 seconds.
Step-by-step explanation:
Remark
The rockets are at the same height when f(x) = g(x) [see below] are the same. So you can equate them.
Givens
f(x) = - 16x^2 + 74x + 9
g(x) = -16x^2 + 82x I have changed this so you don't have 2 f(x)s
Solution
- f(x) = g(x)
- -16x^2 + 74x + 9 = -16x^2 + 82x Add: 16x^2 to both sides
- -16x^2+16x^2+74x + 9 = -16x^2+16x^2 + 82x Combine terms
- 74x + 9 = 82x Subtract 74x from both sides
- 74x - 74x + 9 = 82x - 74x Combine
- 9 = 8x Divide by 8
- 9/8 = 8x/8
- x = 1 1/8 Convert to decimal
- x = 1.125
- x = 1.13 [rounded]
Length of deck is 40 feet
<h3><u><em>Solution:</em></u></h3>
Sam wants the deck to have an overall perimeter of 60 feet
Perimeter of rectangular deck = 60 feet
Let "L" be the length of rectangle and "W" be the width of rectangle
Given that plans for a rectangular deck call for the width to be 10 feet less than the length
Width = length - 10
W = L - 10 ------ eqn 1
<em><u>The perimeter of rectangle is given as:</u></em>
perimeter of rectangle = 2(length + width)
Substituting the known values we get,
60 = 2(L + L - 10)
60 = 2(2L - 10)
60 = 4L - 20
80 = 4L
L = 20
Thus the length of deck is 20 feet
