Ok, so alternate exterior angles are congruent.
So 6x+18=x+93
So we want to get x on the side by itself, to do this we would first subtract 18 from both sides.
This leaves us with the equation
6x=x+75
We will the subtract a from both sides
So the equation is now 5x=75
Well divide both sides by 5 so we can have x completely alone
We are left with the equation
x=15
Now to find the measure of angle b, we plug x into the spot
So 15+93=108°
So the measure of angle B, the answer is 108°
