Standard form is ax+by=c
normally a is positive and a and b are integres
y=mx+b
m=slope
b=yint
y=1/2x+3
minus 1/2 x both sides
-1/2x+y=3
times -2
x-2y=-6

It tells you that over these intervals the balloon is going at a constant speed.
Bryan does indeed have enough money to pay back Jennifer.
We have the 2 numbers -15 and 20. The absolute values of those numbers are 15 and 20.
All we have to do is subtrace 15 from 20. We have the result of positive 5, meaning Bryan will still have $5 left over.
1 3/4 for each batch to make 2 1/2 batches you need to take the amount of raisins for one batch 1 3/4 and multiply it by 2 1/2 the amount of batches.
1 3/4*2 1/2= 4 3/8 cups of raisins