can somone help me pls ?

[tex]\huge\mathtt{Hello!}[/tex]
[tex](6x - 23) = (4x + 9)[/tex]
[tex]6x -4x = 9 + 23[/tex]
[tex]2x = 32[/tex]
[tex]x = 16[/tex]
It is because the sides are equal, so the angles opposite to them also are equal.
Have a nice day!