Answer:
y = 4.25x
Explanation:
Given that:
After 2 week he has used 8 1/2 cups of dog food after 5 week he has used 21 1/4 cups, we can write this in coordinate form (x, y) where;
y is the amount of dog food
x is the time in weeks
The coordinates are (2, 8 1/2) and (5, 21 1/4)
get the slope m:
m = y2-y1/x2-x1
m = (21 1/4 - 8 1/2)/5-2
m = (85/4-17/2)/3
m = (85-34/4)/3
m = 51/12
m = 4.25
Get the intercept c:
Substitute any of the points say (2, 17/2) and m = 51/12 into the equation
y = mx+c
17/2 = 51/12(2) + c
17/2 = 51/6 + c
c = 17/2 - 51/6
c = 51-51/6
c = 0
Get the required equation:
substitute m - 4.25 and c = 0 into y = mx+c
y = 4.25x + 0
Hence the required equation is y = 4.25x