Answer:
Please see the attachments. For reasons I cannot fathom, the Brainly censor seems to think there are unapproved words contained in this text, so I cannot post it as text. Among other things, that means you probably will not be able to copy and paste the formulas into your spreadsheet—you will have to type them.
I apologize if you are offended by any of the words contained in this answer. I hope you will take them in the intended context—a math problem about the use of Excel.
Why now :cccccccccccccccccc
1. Slope 3/4, through (4,-1)
y = 3/4 x + b
-1 = 3/4(4) + b
-1 = 3 + b
-1 - 3 = b
-4 = b
y = 3/4 x - 4
2. Slope = - 1/2, through (3,0)
y = -1/2 x + b
0 = -1/2(3) + b
0 = -1.5 + b
0 + 1.5 = b
1.5 = b
y = -1/2 x + 1.5
The water bill was 1/5 of the total, so was 0.2*$540 = $108.