Answer:
The speed of the jet is 
Step-by-step explanation:
The speed traveled by the jet can be found using the relationship between distance and time. Because the problem gives the values for distance and time, they must be replaced in the equation and in this way the requested speed will be found.
1. Write the general equation for the speed:

2. Replace the values of distance and time on the general equation for the speed and make the mathematical operations:


Therefore the speed of the jet is 
Answer:
28x + 7y = 14.
Step-by-step explanation:
Just add the 28x to each side.
Answer:
i think D
Step-by-step explanation:
Simply it as follows:
1 + 39 = 40
2 + 38 = 40 etc
18 + 22 = 40
19 + 21 = 40
There are 19 of these plus 40 itself . . .therefore 20 of them
20 x 40 = 800
And finally the last number not used, 20
Therefore 800 + 20 = 820