Answer:
x=3
Step-by-step explanation:
Answer: 
This is the same as writing (n-m)/n
Don't forget about the parenthesis if you go with the second option.
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Explanation:
The probability that she wins is m/n, where m,n are placeholders for positive whole numbers.
For instance, m = 2 and n = 5 leads to m/n = 2/5. This would mean that out of n = 5 chances, she wins m = 2 times.
The probability of her not winning is 1 - (m/n). We subtract the probability of winning from 1 to get the probability of losing.
We could leave the answer like this, but your teacher says that the answer must be "in the form of a combined single fraction".
Doing a bit of algebra would have these steps

and now the expression is one single fraction.
(a) Truck carries 90 gallons of diesel fuel to 660 miles.
So, 1 gallon of diesel fuel to 660/90 = 22/3 miles.
30 gallons of diesel fuel to = 220 miles.
Hence, if x-axis represents the number of miles and y-axis represents the number of gallons, then, (660, 90) and (220, 30) are points on the graph.
Join (660, 90) and (220, 30), we get the graph of a line.
Note that (0, 0) is also a point on the line.
Equation of the line is .
(b) x represents the number of miles. Therefore, the possible values for x is the closed interval [0, 660].
Hence, the domain of the function is [0, 660].
(c) Origin represents that the truck is not moving and there is no diesel fuel loaded in the truck.