Hello,
N is closed for an opération(µ) means that
a,b ∈ N : a µ b ∈N (i suppose so)
Answer (1) ex 2/3 ∉ N
Answer (4) ex 2-3 ∉ N
∀ a,b ∈ N: a+b ∈N is true ; not a answer.
∀ a,b ∈ N: a*b ∈N is true ; not a answer.
Her check register will have a surplus of 64 dollars compared to her actual balance.
example
100 +32 = 132 (incorrect)
100 -32 = 68 (correct)
132 -68 = 64 surplus
A. 32500
b. 60,400
c. 2.4 x 10 ^ -6
d. 1.47 x 10 ^3
The answer is B. 2x-y=0, because parallel lines have the same slope (2x), and when you substitute 0 for Y, you get 0 for X-- the origin, (0,0)
