A biologist created the following graph to show the relationship between the temperature of water (x), in degrees Celsius, and the number of insect larvae (y) in the water:

graph of y equals minus 2 times the square of x plus 20 times x plus 400

What do the x-intercepts of the graph represent?

There were 20 larvae at 0 degrees Celsius.
There were 10 larvae at 0 degrees Celsius.
The water has no larvae at −10 degrees Celsius and 20 degrees Celsius.
The water has maximum larvae at −10 degrees Celsius and 20 degrees Celsius.

Question

A biologist created the following graph to show the relationship between the temperature of water (x), in degrees Celsius, and the number of insect larvae (y) in the water:

graph of y equals minus 2 times the square of x plus 20 times x plus 400

What do the x-intercepts of the graph represent?

 There were 20 larvae at 0 degrees Celsius.
 There were 10 larvae at 0 degrees Celsius.
 The water has no larvae at −10 degrees Celsius and 20 degrees Celsius.
 The water has maximum larvae at −10 degrees Celsius and 20 degrees Celsius.

anonymous · Answer

attachment

anonymous · Answer

@welshfella

anonymous · Answer

what does the y variable represent?
what is the value of the y variable at the x intercepts?

anonymous · Answer

thats what I need help with

anonymous · Answer

did you read the info?  it states what y is.

anonymous · Answer

Oh yeah the number of insect larvae

anonymous · Answer

k, great.  do you know what an x intercept is?

anonymous · Answer

yeah a point on the graph where y is zero

anonymous · Answer

excellent!  so in terms of the problem, what is 0 at the x intercept(s)?

anonymous · Answer

x plus 20 times x plus 400?

anonymous · Answer

no... you just said that an x intercept is "a point on the graph where y is zero."  What does y represent, again?

anonymous · Answer

Ugh this is so confusing

anonymous · Answer

not helping

anonymous · Answer

I don't get any of this

anonymous · Answer

suppose you are in a pool of water.  what happens as the water gets hotter?  will you survive no matter what temperature the water rises to?

similarly, what happens as the water gets cooler?  will you survive no matter what temperature the water lowers to?

x represents the water temperature and y is the number of (living) larvae.  doest the graph make a little more sense now?

what happens as x increases (from x = 0)?  can the water temp rise as high as we want and still keep some larvae alive or at some point will it kill all the larvae?  if it does, what is that point?

similarly for decreasing water temperature?

anonymous · Answer

Ohhh I get it

anonymous · Answer

Hold on one second

anonymous · Answer

Is it C) The water has no larvae at −10 degrees Celsius and 20 degrees Celsius.?

anonymous · Answer

what do you think?  you must become confident (right or wrong)!  if you have no investment you won't care.  the more you invest, the more you will care and the more you will learn, especially when you are wrong.