The answer is 54.
Angle 6 is equal to angle 7 so we can substitute angle 7 in for any equations that require angle six what we would want to do is (13x + 9)°+(5x + 9)°= 180°, then you would combine like terms which would then give you 18x+18=180 after this you want to isolate your variable by subtracting 18 from both sides which would give you 18x=162 then you would divide 162 by 18 to give you x=9 next to find angle 6 you would substitute x in the equation so it would be (5(9)+9) 5 multiplied by 9 then add 9 which would give you 45 + 9 which equals out to 54.