Question 1060800
Exterior angles add to 360
we know one is 107, so 5x+2 and 5x+5=253, what is left
That is 10x+7=253
10x=246
x=24.6
One is 125 (mB) and the other is 128 (mC), substituting 123 for 5x.
Note: I put in the plus sign.  If they are minus, the answer will be different.