∠( 2x + 36 ) and ∠4x are interior angles on the same side of transversal, which means their sum will add up to 180° .
Which means :-
To find whether or not we have found out the correct value of x, let us place 24 in the place of x :-
Then :-
As , the sum of both these angles are adding upto 180° (84+96=180) , we can conclude that we have found out the correct value of x .
Therefore, the value of :-