A laboratory test exposes 100 weeds to a certain herbicide. Which equation best models the data in the table?

WEEK 0.....1...2...3...4...5
# of WEEDS100..82.64.39.42.0

y = 100
y = x + 100
y = 20x + 5
y = –20x + 100

Question

A laboratory test exposes 100 weeds to a certain herbicide. Which equation best models the data in the table?

WEEK          0.....1...2...3...4...5
# of WEEDS100..82.64.39.42.0

y = 100
y = x + 100
y = 20x + 5
y = –20x + 100

anonymous · Answer

If it's multiple choice, you could just test all the answers using week as x and #weeds as y.

anonymous · Answer

None of those functions model it exactly, but one comes pretty close.
If you're going to test them, I recommend graphing all those lines on top of the scatter plot of the actual data to see which is best.