Only two real numbers satisfy x² = 23, so A is the set {-√23, √23}. B is the set of all non-negative real numbers. Then you can write the intersection in various ways, like
(i) A ∩ B = {√23} = {x ∈ R | x = √23} = {x ∈ R | x² = 23 and x > 0}
√23 is positive and so is already contained in B, so the union with A adds -√23 to the set B. Then
(ii) A U B = {-√23} U B = {x ∈ R | (x² = 23 and x < 0) or x ≥ 0}
A - B is the complement of B in A; that is, all elements of A not belonging to B. This means we remove √23 from A, so that
(iii) A - B = {-√23} = {x ∈ R | x² = 23 and x < 0}
I'm not entirely sure what you mean by "for µ = R" - possibly µ is used to mean "universal set"? If so, then
(iv.a) Aᶜ = {x ∈ R | x² ≠ 23} and Bᶜ = {x ∈ R | x < 0}.
N is a subset of B, so
(iv.b) N - B = N = {1, 2, 3, ...}
Evaluate the expression using x = –1 and y=3.

1. Substitute the values for the variables.
we plug in -1 for x and 3 for y


2. Identify grouping symbols, beginning with the innermost symbols.

We take exponent and then we multiply
3. Determine and apply the rules of exponents to simplify

(-1)^4 = -1 * -1 * -1 * -1 = 1
(3)^3 = 3*3*3= 27

4. Evaluate.

162
The value of the expression is 162
10x6=60 pounds
36x12=432 ounces which is 27 pounds
60+27=87
$22.50
20 pounds -12.00
50 pounds-.50
30 pounds since there is 17 pounds left -10
$22.50 in total
Hope this is what you needed
If 30 textbooks weigh 144, you do 144/30 to calculate each unit
So the answer is 4.8