SOLUTION: the temperature outside dropped 13f in 7 hours.the final temperature was -2f. what is the starting temperature

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Question 1091665: the temperature outside dropped 13f in 7 hours.the final temperature was -2f. what is the starting temperature
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
I think the tricky part is that the final temp
is the temp after the 7 hrs
What you have given is a slope and a point
You are free to say that the starting temp
is at time +t+=+0+, and the final time is at
time +t=+7+
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Use the point slope formula
Let the starting temp = +T+
+%28+-2+-+T+%29+%2F+%28+7+-+0+%29+=+-13%2F7+
( note that the drop in temp gives you a negative slope )
+%28+-2+-+T+%29%2F7+=+-13%2F7+
+-2+-+T+=+-13+
+T+=+11+
The starting temp is 11 f
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Also, the equation would be:
+T+=+%28-13%2F7%29%2At+%2B+11+