Step-by-step explanation:
[tex]\angle{FJG} + \angle{GJH} = \angle{FJH}[/tex]
[tex]\Rightarrow (6x - 15) + (x + 8) = 168°[/tex]
[tex]\Rightarrow 7x - 7 = 168[/tex]
and this gives us
[tex]7x = 175°[/tex] or [tex]x = 25°.[/tex]
