Question

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

Answer 1

m || n

3x - 15 = 105
3x = 120
x = 40

answer
x = 40

Answer 2

(A) x=40

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,
`105^(\circ)=3x-15^(\circ)`

⇒
`105^(\circ)+15^(\circ)=3x`

⇒
`120^(\circ)=3x`

⇒
`(120)/(3)=x`

⇒
`x=40`

Thus, the value of x is 40, hence option A is correct.