Step-by-step explanation:
<H + <G = <GFD
30° + 10x + 12° = 15x + 7 °
42° + 10x = 15x + 7°
42° - 7° = 15x -10x
5x = 35°
Therefore x = 7°
Now
<G = 10x + 12° = 10 * 7° + 12° = 70° + 12° = 82°