I believe the answer is a.
With what you've jus given me, no. is there an equation or something to go along with this question?
All triangles must have angles that add up to the same amount of degrees, so if the two triangles share one exact point, it is assumed that those angles would be the same. Basically just use the fact that the sides are the same and marked by dashes, and the missing line can be proven with the use of the angles that are in between the point that both share.
When factoring, it's easier to "pick out" the GCF first because it makes it simpler to factor even further. Otherwise, you will be troubled with lots of numbers and variables, so it will just get confusing.
