I'm actually just <u>assuming</u> that you mean arc NO. Proceeding with that...
Angle NMO is an inscribed angle which intercepts arc NO. Angle NPO is also an inscribed angle that intercepts arc NO. Because they both intercept the same arc, both inscribed angles have the same measure. Therefore,
9x - 3 = 4x + 12
Solving for x:
5x = 15
x = 3. Plug 3 in for x in either one of the equations to get that angles NMO and NPO measure
9(3) - 3 = 24°
The rule is that inscribed angles measure HALF of the arcs they intercept, so the measure of arc NO is 48°
They are not. The easiest way to tell this is by multiplying the last number of each parenthesis together. This should always result in the last number in the equation. However, -8*5 does not equal -30, so these are not the true factors.