Answer:
x(3/4-y/4)
Step-by-step explanation:
3/4x-1/4xy=x(3/4-y/4)
Let
x--------> the time in hours
y-------> the distance in miles
we know that
The speed is equal to

in this problem


<u>Equation First Train</u>

<u>Equation Second Train</u>

---------> equation 
Substitute the values of
and
in the equation 

Solve for x


therefore
<u>the answer is</u>

The answer is 90/91. 6 1/2 - 7/8 divided by 5 11/16. Turn 6 1/2 and 5 11/16 to an improper fraction. 6 1/2= 13/2. 5/11= 91/16. Then you have to get each fraction to have equal denominators. All of them can have a denominator of 16. So you times everything to get a denominator of 16. 13/2= 104/16. 7/8=14/16. 91/16 stays the same because the denominator is already 16. Next you subtract 104/16 and 14/16 and get 45/8.( because you need to put it in simplest form.) Lastly you divide 45/8 by 91/16 and get 90/91.