Answers:
x = 7
angle NML = 24 degrees
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Work Shown:
OML is the largest angle
OMN and NML are the two pieces that make up that largest angle.
They add like so
OMN + NML = OML
(9x) + (3x+3) = 10x+17
12x+3 = 10x+17
12x-10x = 17-3
2x = 14
x = 14/2
x = 7
You have the correct x value.
Now use this to find each angle
angle OMN = 9x = 9*7 = 63
angle NML = 3x+3 = 3*7+3 = 24
angle OML = 10x+17 = 10*7+17 = 87
As a check,
OMN+NML = 63+24 = 87
which matches with the measure of angle OML.
This confirms OMN+NML = OML to be true and it confirms our answers.