1. 42.3
When x=3 and y=7, the expression becomes
2. 32.6
When r=12 and s=4, the expression becomes
3.
We can call the initial weight of the object, and its weight increases by 0.5 for each month, so must add
. Therefore, the expression for the weight will be
4. -11
For c = -2:
5. +3
For x = -6:
6. 14
For k = 20 and m = -2:
7. -60
For p = -26:
8.
In fact, b represents the number of baseballs, while s represents the number of softballs. Each ball weights 5.25 ounces, so the total weigth of the baseballs is . Similarly, each softball weighs 6.5 ounces, so the total weight of the softballs will be
9. B. 157.5 pounds
The weight of the crate is 22.5 pounds.
The weight of each box is 11.25 pounds, and we have n=12 boxes, so the expression for the total weight will be
10.
We can assume that the initial amount of water in the container is 34 ounces. Every day, 1.5 ounces of water are lost: calling d the number of days, this means that after d days, we will have lost ounces of water. Therefore, we must use a negative sign, and the final expression will be
11. 3.75 miles from the destination
The initial distance from the destination is d = 60. At each hour, the freigth covers a distance of 22.5 miles. Calling h the number of hours, the distance from the destination can be expressed as
And substituting h = 2.5 (number of hours), we find the distance from the destination after 2.5 hours:
12. 107.5 feet
The initial elevation of the elevator is 85.5 feet. At each second, the elevation increases by 2.75 feet: if we call t the number of seconds passed, the elevation of the elevator can be expressed as
And substituting t=8 (number of seconds), we find the elevation after 8 seconds: