Triangle abc is similar to triangle xyz. ab=5x+25, bc=7x+44, yz=29, xz=45, xy=14 find x

The fraction  -109/47 (see note below)



Explanation:

Triangle ABC is similar to Triangle XYZ. This means that 
AB/BC = XY/YZ
is one proportion we can form

Plug in the given expressions and then isolate x
AB/BC = XY/YZ
(5x+25)/(7x+44) = 14/29
29(5x+25) = 14(7x+44)
29(5x)+29(25) = 14(7x)+14(44)
145x+725 = 98x+616
145x-98x = 616-725
47x = -109
x = -109/47

note: its possible your teacher made a typo since we got a negative fraction here. I would ask your teacher to double check.