What is the value of x for which m || n?
x = 40
x = 5
x = 105
x = 30

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, [tex]105^{\circ}=3x-15^{\circ}[/tex]
⇒[tex]105^{\circ}+15^{\circ}=3x[/tex]
⇒[tex]120^{\circ}=3x[/tex]
⇒[tex]\frac{120}{3}=x[/tex]
⇒[tex]x=40[/tex]
Thus, the value of x is 40, hence option A is correct.