I need help with geometry

The triangles seem congruent due to the symbols on the sides and angle so the equations are equivalent allowing us to make this equation:
9x-17 = 4x+8

Using this we solve it to get x.

Add 17 to both sides.
9x = 4x+25

Subtract 4x from both sides.
5x=25

Divide both sides by 5 to make x by itself.
x=5.

So x is 5.