The probability is 0.2743.
Calculating the z-score for this time, we have:
z = (X-μ)/σ
z = (96-90)/10 = 6/10 = 0.6
Using a z-table (http://www.z-table.com) we see that the area to the left of this, less than this score, is 0.7257. This means the area greater than this would be 1-0.7257 = 0.2743.
To factor the given function, find a term that is divisible by both terms. For this problem, the factor would be 2, since 2x^2 and -18 are both divisible by 2.
2(x^2 - 9)
You could further factor out x^2 - 9 because it is factorable by (x - 3) and (x + 3). Thus, it would be
2(x -3)(x+3)
The curves cross at coordinates (x, y) = (1, 4). The x-value is said to represent the increase in temperature, while the y-value is said to represent the numbers of visitors and those and who leave early.
The "solution" is the temperature change at which the number of visitors is equal to the number who leave early.
