X^9 * x^0 * x^-4 * x
1 answer:
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Answer:
Step-by-step explanation:
This is a Combination (as in permutation vs combination) question the symbol (n r) refers to "n choose r". This is sometimes written as nCr
i.e the question is asking you to find how many combinations each will yield when you chose r items from n item without repetition and order does not matter.
I will only do the first question for you and you can just follow the same steps to solve the rest of the questions.
Recall that
Consider question a) we are given (5 1) or ₅C₁
we can see that n = 5 and r = 1
If we substitute this into the formula:
₅C₁ = (5!) / [ (1!)(5- 1)!]
= (5!) / [ (5- 1)!]
= (5!) / (4!)
= (5·4·3·2·1) / (4·3·2·1)
= 5
hence ₅C₁ = 5
Answer:
<h2>height = 12 cm</h2>Step-by-step explanation:
Area of a triangle is given by
where
b is the base
h is the height
From the question
Area = 21 m²
The statement
The height of a triangle is 8 m more than the length of the base is written as
h = 8 + b
Make b the subject
That's
b = h - 8
Substitute the expression into the above formula and solve for the height
That's
Multiply through by 2
h² - 8h = 48
h² - 8h - 48 = 0
(h + 4)(h - 12) = 0
h + 4 = 0 h - 12 = 0
h = - 4 h = 12
Since the height cannot be a negative number we have the final answer as
<h3>height = 12 cm</h3>Hope this helps you