Answer:
x = 11 
Explanation:
Assuming that segment EG is a diameter we can solve this using the straight angle theorem ( Which states that angles on a straight line add up to equal 180. Also note that central angles and there corresponding arcs are congruent. ) 
We are also told that CH is a bisector. 
A bisector splits an angle into TWO EQUAL parts. 
mDG is split into mDC and mCG 
So mDC = mCG 
This meaning that because mDC = 7x + -1 , mCG also equals 7x - 1 
Leading to us having enough information to use the straight line theorem ( which also works with half circles and arcs. ) 
So 180 = 2 ( 7x - 1 ) + 2x + 6 
now we solve for x 
step 1 distribute the 2
2 * 7x = 14x
2 * - 1 = -2 
now we have 180 = 14x - 2+ 2x + 6 
step 2 combine like terms 
14x + 2x = 16x
-2 + 6 = 4 
now we have 180 = 16x + 4
step 3 subtract 4 from each side
4 - 4 cancels out 
180 - 4 = 176
Now we have 176 = 14x
step 4 divide each side by 14 
176 / 16 = 11
14x/14 = x
we're left with x = 11