20 I think. If I’m wrong don’t roast me please.
So this inequality is going to be written as 9(x + 6) > 99
Firstly, you want to foil 9(x + 6), which will look like this: 9x + 54 > 99
Next, subtract 54 on both sides of the equation: 9x > 45
Lastly, divide both sides by 9, and your answer will be x > 5
I agree with your answer "supplementary". The two angles combine to form 180 degrees, aka a straight angle
Your teacher seemed to have made a typo.
Since he sold it for $75 more,
% Mark Up = Mark Up/ Cost Price x 100%
% Mark Up = 75 / 125 x 100% = 0.6 x 100% = 60%
Percent Mark Up = 60%
Hope this helps :)