Answer:
30
Step-by-step explanation:
Here, it is given that the Z – score corresponding to the score X = 45 is 1.5 and the Z – score corresponding to the score X = 40 is...
Z =
So:
1/ 1.5 = and 1 =
. solve the both equations, we found out:
<=> S = 10
=> M = 30
Hence, mean is:
M = 45 -1.5S = 45 - 1.5 (10) = 30
We have to find the value of the expression
We know that the below values.
Hence, in order to find the value of the given expression, we can first rewrite it in terms of
Now, we know that
Hence, we have
C is the correct option.
Answer:
see explanation
Step-by-step explanation:
Given
9n² - n - = 0 ← multiply through by 3 to clear the fraction
27n² - 3n - 2 = 0 ← factoring
Consider the factors of the product of the n² term and the constant term which sum to give the coefficient of the n- term
product = 27 × - 2 = - 54 and sum = - 3
The factors are - 9 and + 6
Use these factors to split the n- term
27n² - 9n + 6n - 2 = 0 ( factor the first/second and third/fourth terms )
9n(3n - 1) + 2(3n - 1) = 0 ← factor out (3n - 1) from each term
(3n - 1)(9n + 2) = 0
Equate each factor to zero and solve for n
3n - 1 = 0 ⇒ 3n = 1 ⇒ n =
9n + 2 = 0 ⇒ 9n = - 2 ⇒ n = -