Answer:
(A) x=40
Step-by-step explanation:
Given: It is given that m is parallel to n.
To find: The value of x.
Proof: It is given that m is parallel to n, from the figure it can be seen that 105° and (3x-15)° forms alternate exterior angles which are equal in measure because m is parallel to n.
Thus,
⇒
⇒
⇒
⇒
Thus, the value of x is 40, hence option A is correct.