Given that the mean is $9.5 and the standard deviation is $1.30, the standard error will be given by:
σ/√n
where
σ-standard deviation
n=sample size
thus, we shal have:
1.30/√20
=0.2906
Next we find the margin error
0.2906*2=0.581
thus the confidence interval will be:
(9.5+0.581, 9.5-0.581)
=(10.081,8.919)
Xy 14
x + y = -4
x + y = -4
x - x + y = -x - 4
y = -x - 4
xy = 14
x(-x - 4) = 14
x(-x) - x(4) = 14
-x² - 4x = 14
-x² - 4x - 14 = 0
-1(x²) - 1(4x) - 1(14) = 0
-1(x² + 4x + 14) = 0
-1 -1
x² + 4x + 14 = 0
x = -(4) ± √((4)² - 4(1)(14))
2(1)
x = -4 ± √(16 - 56)
2
x = -4 ± √(-40)
2
x = -4 ± 2i√(10)
2
x = -2 ± i√(10)
x + y = -4
-2 ± i√(10) + y = -4
- (-2 ± i√(10)) - (-2 ± i√(10))
y = -2 ± i√(10)
(x, y) = (-2 ± √(10), -2 ± √(10))
The two numbers that multiply to 14 and add up to -4 are -2 ± i√(10).
An equation must contain an equals sign. That means answer A is the only one that is an equation.
Hope this helps!!
