D=rtthe distances are not equal, but they add up to a total of 400 milesone bus goes 55mph times t so that is 55t (that represents the distance in one direction)the other bus goes 45 mph,so that is 45t (that represents the distance in the other direction)the total distance is 400, so the equation is distance one direction + distance the other direction = 400your equation is 55t + 45t = 400 100t = 400 t= 4 hoursso after 4 hours they will be 400 miles apart
6 - a =

(9a - 18)
First, simplify

to

/ Your problem should look like:
Second, multiply both sides by 3. / Your problem should look like:
Third, expand. / Your problem should look like:
Fourth, add 3a to both sides. / Your problem should look like:
Fifth, simplify 9a - 18 + 3a to 12a - 18. / Your problem should look like:
Sixth, add 18 to both sides. / Your problem should look like:
Seventh, add 18 + 18 to get 36. / Your problem should look like:
Eighth, divide both sides by 12. / Your problem should look like:
Ninth, since 3 goes into 12 to get 36, simplify

to 3. / Your problem should look like:
Tenth, switch sides. / Your problem should look like:

Answer:
a = 3 (one solution)
Answer: eight hundred ninety thousand, seven hundred four
Answer:
The probability is 9/266
Step-by-step explanation:
The first thing to do here is get the total number of marbles = 5 + 7 + 9 = 21 marbles
Now we are drawing the marbles without replacement, this means once a marble is drawn there is a decrease in the total number of marbles left.
The probability of drawing a green marble initially = number of green marbles/ total
number of marbles = 9/21 = 3/7
Now, we want to draw a blue marble
There are 5 blue marbles and we have already drawn one marble from the total. So the probability of drawing a blue marble would be 5/20 = 1/4
And lastly, another green marble
That would make 6 green marbles left and a total of just 19 left. So the probability at this point for green marbles = 6/19
Having and in probability means we multiply all
So this means the probability we are calculating is; 3/7 * 1/4 * 6/19 = 18/(28 * 19) = 9/(14 * 19) = 9/266
Answer:
√20,
√19,
√17,
√23
Step-by-step explanation: