Answer:
x = 1
Explanation:
Δ ABC and Δ DEF are congruent ( SAS postulate )
Thus corresponding sides are congruent that is
BC = EF , substitute values
13x - 12 = 7x - 6 ( subtract 7x from both sides )
6x - 12 = - 6 ( add 12 to both sides )
6x = 6 ( divide both sides by 6 )
x = 1