2018 is the 70th term of the progression.
Explanation
We start out finding the common difference of the progression:
46-17 = 29
Now we write the explicit formula for the sequence. It is of the form

We set this equal to 2018 to see if the answer is a whole number. If it is, it will be the term number that gives us 2018:
2018=17+29(n-1)
Using the distributive property,
2018=17+29*n-29*1
2018=17+29n-29
Combine like terms:
2018=29n-12
Add 12 to both sides:
2018+12=29n-12+12
2030=29n
Divide both sides by 29:
2030/29=29n/29
70=n
Since n=70, this means 2018 is the 70th term of the sequence.
Answer:
∡ABC=55°
Step-by-step explanation:
<u>Step 1: Identify all angles</u>
∠A=(x+45)°
∠B=(6x+5)°
∠C=(3x)°
∠ABC=(180-∠B)°=(180-(6x+5))°
<u>Step 2: Use the Triangle Angle Sum Theorem</u>
∠A+∠ABC+∠C=180°
(x+45)+(180-(6x+5))+(3x)=180
x+45+180-6x-5+3x=180
-2x+45+180-5=180
-2x+45-5=0
-2x+40=0
-2x=-40
x=20
<u>Step 3: Plug in x=20 for ∠ABC</u>
∠ABC=(180-(6x+5))°
(180-6(20)-5)°
(180-120-5)°
(60-5)°
55°
So ∡ABC=55°
I have a good record of guessing the right one so I would say #1.