In the diagram below BO, OC, m<COY=2d+40, m<BOY=d-10 find m<COY

I need help anyone please help me. Out with this equation I need show this work in front of the class please HELP

Can you please link us to a picture of the diagram? If we had that, we'd be able to tell you how to solve it. Otherwise, there's no way of knowing what you mean.

I'll list some of the possibilities to help you, though.

If the angles are equal (vertical angles), then...

2d+40 = d-10
d = -30
m
If the angles add up to 180º (supplementary), then...

2d+40+d-10 = 180
3d+30 = 180
3d = 150
d = 50
m
Finally, if the angles add up to 90º (complementary), then...

2d+40+d-10 = 90
3d+30 = 90
3d = 60
d = 20
m
Chose whichever solution is applicable.