They are parallel to one another
I think
J,BB,S
(I shortened name to letter)
Option A is true because the sum of angles in a triangle is 180, so we can rule that one out immediately.
We can solve for x for the other 3 options by setting up this equation:
7x+2 + 4x+7 + 8x = 180 | Simplify
19x + 9 = 180 | Subtract 9
19x = 171 | Divide by 19
x=9
Now we can substitute x into all the values:
<J = 7x+2 = 65
<L = 4x+7 = 43
<K = 8x = 72
Looking at the options again, we can see that A, B, and D are true, leaving C to be false.
7-4=3
10-7=3
13-10=3
we can see that this is an arithmetic sequence with a difference of 3
the nth term=the first term +(n-1) times the difference
so a(n)=4+3(n-1)