The first thing we are going to do for this case is define variables.
We have then:
x: number of gallons of water
y: total weight
We then have an equation of the form:
[tex]y-yo = m (x - xo)
[/tex]
Where,
[tex]m = (y2 - y1) / (x2 - x1)
[/tex]
Substituting values:
[tex]m = (196.8 - 113.4) / (20 - 10)
m = 8.34[/tex]
We choose an ordered pair:
[tex](xo, yo) = (10, 113.4)
[/tex]
Substituting values:
[tex]y-113.4 = 8.34 (x - 10)
[/tex]
Rewriting:
[tex]y = 8.34x - 83.4 + 113.4
y = 8.34x + 30[/tex]
Answer:
y = 8.34x + 30