Explanation:
14.
G must be congruent to B (the vertexes with the right angle).
and then
GH = GF = CB = AB (they are both isoceles triangles meaning both legs have the same length, and then these legs must be congruent bergen the triangles, so, in fact, all 4 sides must have equal length).
therefore,
5y mm = 25 mm
y = 5
(2x + 5) mm = 25 mm
2x + 5 = 25
2x = 20
x = 10
(3z + 14) mm = 35 mm
3z + 14 = 35
3z = 21
z = 7