Mr. Maxwell randomly assigns seventh-grade students to one of four study groups: blue, red, green, purple. What is the probability that Mr. Maxwell will assign the next student to the green group?

x-intercept:

A line that crosses the graph at x-axis.

i.e substitute y = 0 and solve for x.

As per the statement:

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

Given the graph:

Substitute y = 0  we have;

⇒

⇒

⇒

⇒

⇒

By zero product property we have;

x-20 =0 and x+10 = 0

⇒x = 20 and x = -10

Therefore,  the x-intercept represents the water has no larvae at −10 degrees Celsius and 20 degrees Celsius.