The answer is 1224. You do 70.5 + 65.5, divided by two, then you take that answer and multiply by 18 to get 1224
Answer:
The answer is below
Step-by-step explanation:
From the table, the mean (μ) = 1390.75 and the standard deviation (σ) = 518.75
The confidence level (C) = 90% = 0.9
α = 1 - C = 1 - 0.9 = 0.1
α/2 = 0.1 / 2 = 0.05
The z score of α/2 (0.05) is the same as the z score of 0.45 (0.5 - 0.05) which is equal to 1.645.
The margin of error (E) is given as:

The confidence interval = μ ± E = 1390.75 ± 228.07 = (1162.68, 1618.82)
The confidence interval is between 1162.68 and 1618.82.
Answer:
# 1,3 and 6
Step-by-step explanation:
X + y = 12 . . . . . . . . (1)
x - 3y = -30 . . . . . . . (2)
(1) - (2): 4y = 42
y = 10.5
Answer:
x³ + 7x² - 6x - 72
Step-by-step explanation:
Given
(x + 6)(x + 4)(x - 3) ← expand the second and third factor, that is
(x + 4)(x - 3)
Each term in the second factor is multiplied by each term in the first factor, that is
x(x - 3) + 4(x - 3) ← distribute both parenthesis
= x² - 3x + 4x - 12 ← collect like terms
= x² + x - 12
Now multiply this by (x + 6) in the same way
(x + 6)(x² + x - 12)
= x(x² + x - 12) + 6(x² + x - 12) ← distribute both parenthesis
= x³ + x² - 12x + 6x² + 6x - 72 ← collect like terms
= x³ + 7x² - 6x - 72