To solve the problem we must know about Z-Score.
<h3>What is Z-score?</h3>
A Z-score helps us to understand how far is the data from the mean. It is a measure of how many times the data is above or below the mean. It is given by the formula,

Where Z is the Z-score,
X is the data point,
μ is the mean and σ is the standard variable.
The life span of an appliance that has a z-score of –3 is 24 months.
Given to us
- Mean, μ = 48 months,
- standard deviation, σ = 8 months,
- Z-Score = -3
<h3> What is the life span of an appliance?</h3>
The life span of the appliance can be calculated using the Z-score formula,

Substitute the values,

Hence, the life span of an appliance that has a z-score of –3 is 24 months.
Learn more about Z-score:
brainly.com/question/13299273
Here, I'll have a try:
This expression is the multiplication of a binomial and a trinomial.. The binomial has two terms, while the trinomial has three terms. Use the distributive property of multiplication,
Step 1, multiply every term of the trinomial with the first term of the binomial, then multiple every term of the trinomial with the second term of the binomial. Use parenthesis to separate each multiplication to avoid confusion.
step 3, simply every multiplication
step 4, add up like trms
13/36 would be the answer I believe
As soon as I read this, the words "law of cosines" popped
into my head. I don't have a good intuitive feeling for the
law of cosines, but I went and looked it up (you probably
could have done that), and I found that it's exactly what
you need for this problem.
The "law of cosines" relates the lengths of the sides of any
triangle to the cosine of one of its angles ... just what we need,
since we know all the sides, and we want to find one of the angles.
To find angle-B, the law of cosines says
b² = a² + c² - 2 a c cosine(B)
B = angle-B
b = the side opposite angle-B = 1.4
a, c = the other 2 sides = 1 and 1.9
(1.4)² = (1)² + (1.9)² - (2 x 1 x 1.9) cos(B)
1.96 = (1) + (3.61) - (3.8) cos(B)
Add 3.8 cos(B) from each side:
1.96 + 3.8 cos(B) = 4.61
Subtract 1.96 from each side:
3.8 cos(B) = 2.65
Divide each side by 3.8 :
cos(B) = 0.69737 (rounded)
Whipping out the
trusty calculator:
B = the angle whose cosine is 0.69737
= 45.784° .
Now, for the first time, I'll take a deep breath, then hold it
while I look back at the question and see whether this is
anywhere near one of the choices ...
By gosh ! Choice 'B' is 45.8° ! yay !
I'll bet that's it !
Answer:

Step-by-step explanation:
the transverse axis is horizontal.
so its a horizontal hyperbola
Center is the origin so center is (0,0)
Equation of horizontal hyperbola is

Given a= 55000 and c= 81000
c^2 = a^2 + b^2
81000^2 = 55000^2 + b^2
subtract 55000^2 on both sides
b = sqrt(81000^2 - 55000^2)= 59464.27
now plug in the values
