Answer is From all those aforementioned, the true statement is: Thanh’s grade is 2.5 standard deviations below the mean of the test grades.
explanation
The z scores are standard deviations. If, for example, a tool returns a z score of +2.5, it means that the result is a standard deviation of 2.5. Very high or very low (negative) z scores associated
with very low p values are at the ends of the normal distribution.
The answer is the third one
Hope this helps! :)
Answer:
x = -3 or x = 3
Step-by-step explanation:
Subtract 9 from both sides.
x^2 - 9 = 0
Factor the left side. There is no common factor of the terms. It is a binomial which is the difference of two squares, so it factors into the product of a sum and a difference.
(x + 3)(x - 3) = 0
Set each factor equal to zero.
x + 3 = 0 or x - 3 = 0
Solve each equation.
x = -3 or x = 3
