Answer:
+ 1) is an even number.
Take any n ∈ N, then n is either even or odd.
• Suppose n is even ⇒ n = 2m for some m ⇒ n(n + 1) = 2m(n + 1) ⇒ n(n + 1) is even.
• Suppose n is odd ⇒ n+ 1 is even ⇒ n+ 1 = 2m for some m ⇒ n(n+ 1) = 2nm ⇒ n(n+ 1)
is even. QED
2. The sum of the first n natural num
Step-by-step explanation:
a>50A is greater than 50
a<50a<50
a≥50A is greater than or equal to 50
a≤50
Answer:
Step-by-step explanation:
It is not a function because there can't be two of the same number on the x-axis.
Answer:
It will take him

of a minute to fill the bottle.
Step-by-step explanation:
I'm really not sure this is right but..
we can solve using proportions. Cross-multiply and divide.

Answer:
x = 107
Step-by-step explanation:
44+29+107=180
a triangle equals 180 with all the degrees added together :)