Answer:
Step-by-step explanation:
7x-=6x-9
7x=6x-9
7x+9=6x-9+9
7x+9=6x
7x+6x=9
13x=9
X=0.69
Answer:
rate of the plane in still air is 33 miles per hour and the rate of the wind is 11 miles per hour
Step-by-step explanation:
We will make a table of the trip there and back using the formula distance = rate x time
d = r x t
there
back
The distance there and back is 264 miles, so we can split that in half and put each half under d:
d = r x t
there 132
back 132
It tells us that the trip there is with the wind and the trip back is against the wind:
d = r x t
there 132 = (r + w)
back 132 = (r - w)
Finally, the trip there took 3 hours and the trip back took 6:
d = r * t
there 132 = (r + w) * 3
back 132 = (r - w) * 6
There's the table. Using the distance formula we have 2 equations that result from that info:
132 = 3(r + w) and 132 = 6(r - w)
We are looking to solve for both r and w. We have 2 equations with 2 unknowns, so we will solve the first equation for r, sub that value for r into the second equation to solve for w:
132 = 3r + 3w and
132 - 3w = 3r so
44 - w = r. Subbing that into the second equation:
132 = 6(44 - w) - 6w and
132 = 264 - 6w - 6w and
-132 = -12w so
w = 11
Subbing w in to solve for r:
132 = 3r + 3(11) and
132 = 3r + 33 so
99 = 3r and
r = 33
Answer:
-45
Step-by-step explanation:
(-3)(-5)(-1 - 2)
(-3)(-5)(-3)
(15)(-3)
-45
1. Since the sales of 8-track players are decreasing by 5.1% per year, we can say that the sales after a year are 94.9% of the sales of the previous year. For succeeding years, we just multiply the percentage a number of times corresponding to the number of years. Forming an exponential function for this we'll get:

where x is the number of years and f(x) is the number of sales.
To find the number of sales in 2013 we just plug in 3 for the value of x:
ANSWER: Emporium sold 333 8-track players in 2013.
2. The half life of Neptunium-229 is modeled by

where A is the final amount and t is the time that has passed in minutes. This just means that the original amount will be multiplied by one half for every 4 minutes.
30 minutes has passed from 7:45 am to 8:15 am. Therefore, we just substitute 30 as the value of t to find the amount of Neptunium remaining by 8:15.
ANSWER: 2.76 grams of Neptunium-229 are remaining at 8:15 am.
3. To find how much annual interest is collected over x years, we just do the same modelling as the previous items. Knowing that the initial amount that Mr. Canonaco deposited into his bank account and that the <span>Dewey, Cheetum, & Howe Credit Union collects 6.25% annual interest per year, the equation will be as follows:
</span>

where x is the number of years and f(x) is the annual interest collected.
Answer:
see explanation
Step-by-step explanation:
The side of the square = x + 2, thus area is equal to
(x + 2)² ← expand using FOIL
= x² + 4x + 4
Given area = 7 then
x² + 4x + 4 = 7 ( subtract 4 from both sides )
x² + 4x = 3 ← as required