In ΔFGH, m∠F = ( x − 9 ) ∘ (x−9) ​∘ ​​ , m∠G = ( 3 x + 8 ) ∘ (3x+8) ​∘ ​​ , and m∠H = ( 9 x − 1 ) ∘ (9x−1) ​∘ ​​ . What is the value of x?