Answer:
x=-2
Step-by-step explanation:
-9+1=-8 so 2x squared =-8
x=-2
Answer:
70°
Step-by-step explanation:
The total angle in a triangle is 180°. The total angle in a straight line is 180°. From the image attached, the ∠DCA must be greater than 45° because ∠BCA is greater than 90°. This means that ∠DCA is not 36° or 38° or 40° but it is 70°.
Therefore ∠DCA = 70°.
∠BCA + ∠DCA = 180° (angle on a straight line)
∠BCA = 180 - ∠DCA = 180 - 70 = 110°
∠BCA + ∠BAC + 40 = 180° (angle in a triangle)
∠BAC = 180 - 110 - 40 = 30°
Answer:
See explanation!
Step-by-step explanation:
The term 9x is comprised of two values: 9 and x. The 9 represents the cost of the general admission tickets. Since the expression is representing the total cost for the group of friends, the number of friends attending must be represented somehow in the equation. Since the $9 is paired with the x, this means that x represents how many of the friends are paying the general admission price. After interpreting both values within the term, the meaning of the term 9x is simply just the total cost of the friends that are paying the general admission price! Hope this helps!
Answer:
Step-by-step explanation:
The imaginary number <em>i</em> signifies the imaginary part of a complex number. The imaginary part of the number is the coefficient of <em>i</em>. The real part is everything else.
__
In (a +bi), (a) is the real part, and (b) is the imaginary part.
In (-9 +8i), (-9) is the real part and (8) is the imaginary part.
Answer:
A sample of 18 is required.
Step-by-step explanation:
We have that to find our
level, that is the subtraction of 1 by the confidence interval divided by 2. So:
Now, we have to find z in the Z-table as such z has a p-value of
.
That is z with a pvalue of
, so Z = 1.88.
Now, find the margin of error M as such
In which
is the standard deviation of the population and n is the size of the sample.
A previous study indicated that the standard deviation was 2.2 days.
This means that 
How large a sample must be selected if the company wants to be 92% confident that the true mean differs from the sample mean by no more than 1 day?
This is n for which M = 1. So



Rounding up:
A sample of 18 is required.