Step-by-step explanation:
Let the number be x, then

A tank with capacity T gallons is empty. Tank will be filled in
minutes
<u>Solution:</u>
Given, A tank with capacity T gallons is empty.
We have to find how many minutes will tank be filled?
Now, Water flows into the tank from pipe X at the rate of X gallons per minute,
And water is pumped out by pipe Y at the rate Y gallons per minute,
Then, together in one minute the amount of water filled will be x – y gallons [as X is greater than Y]
Now, the time take to fill tank = 
Hence tank will be filled in
minutes
-0.0375
-1/2
———- ( 7 1/2 ) =-3/80
100
If they are parallel then the coefficients of x and y will remain the same. Only the constant will change.
2x + 3y = ?
2(-2) +3(3) = -4 + 9 = 5 so ? is 5
ANSWER: 2x + 3y = 5