∠AOC= 180 - 150 =30

So AC=CO* 1/2= 1.5.

So AO= root number (3 2-1.5 2) =1.5 * root number 3.

So point C (-1.5* radical number 3, 1.5) (the second quadrant)

(2) only know M=- root number 3 (the topic is incomplete)

(3) Solve the equations about x and y.

X+2Y=5M

X-Y=9M:

X=23M/3，Y=-4M/3

Substitute X=23M/3 and Y=-4M/3 into 3X+2Y= 17, and get: M=5 1/6 1.