Step-by-step explanation:
always write what you know
circumference
U = 2 x pi x r
r = d/2
U = 39.25
rearrange and solve for r
U / (2 x pi) = r
solve for diameter
2r = d
M + 2m - 6 = -12 + 2m
3m - 6 = -12 + 2m
+6 +6
--------------------------------
3m = -6 + 2m
-2m -2m
-----------------------
1m = -6
/1 /1
m = -6
Y=6 because if you break it down you get (11y+7) =73 then you subtract 7 from both sides to get 11y=66 then you divide 11 on both sides to get y=6