11/2. You can set x+6=3x-5 because when two triangles are congruent then all their corresponding sides and angles are congruent. Then solve for x and you get x=11/2
Since ABC is congruent to DEF we know that side AB is congruent to side DE. Set up the equations for both sides to equal one another (x + 6 = 3x - 5). Solve to find “x”: - 6 = 2x - 5 - 11 = 2x - x = 5.5 Hope this helped :)