30 + 2x = 90
2x = 60
x = 30
Answer:
x = 30
Answer:
-2-2√3, -2+2√3
Step-by-step explanation:
Let x represent one of the numbers. Then the other number is -4-x. We want the product to be -8:
x(-4-x) = -8
-4x -x^2 = -8 . . . . . eliminate parentheses
x^2 +4x = 8 . . . . . . multiply by -1
x^2 +4x +4 = 12 . . . add 4 to complete the square
(x +2)^2 = 12
x +2 = ±√12 = ±2√3
x = -2±2√3
The two numbers are -2-2√3 ≈ -5.4641, and -2+2√3 ≈ 1.4641.
The answer is B, I'm on the test now.
The standard error of the mean is 12.
The standard error of the mean points to the standard deviation of the distribution of a sample mean obtained from a population.
The standard error S.E of the mean can be calculated by using the formula:

where;
- standard deviation
= 24 - sample size n = 4


S.E = 12
Learn more about the Standard error of the mean here:
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