Answer:
The truck travel must to have a constant speed of 
Step-by-step explanation:
we have

where
d expresses a car's distance in feet
t is the number of seconds
<em>Find the distance d for t=8 sec</em>

<em>Find the distance d for t=8.2 sec</em>

The total distance in this interval of 0.2 sec is

<em>Find the speed of the car</em>
Divide the total distance by the time

therefore
The truck travel must to have a constant speed of 
Answer:
the answer is x=2 and y=2
Step-by-step explanation:
-3y=16+5x
-y=(16+5x)3
Answer:
the two numbers are -5 and 1
Step-by-step explanation:
Let x and y be the first number and second number respectively.
According to the question, we can find 2 equations:
2x + 5y = -5
3x + 10y = -5
On solving,
x = -5
y = 1
Answer:
21 and 30
Step-by-step explanation:
x + y = 51
x - y = 9
add the two equations and y's will cancel out
2x = 42 divide by 2
x = 21 so put 21 in for x in the top equation and solve
21 + y = 51
y = 30