Answer: x = 20
We know opposite angles are equivalent so we can set both of these expressions equal to each other to solve for x.
3x + 50 = 6x - 10
50 = 3x - 10 (subtract 3x from both sides)
60 = 3x (add 10 to both sides)
20 = x (divide both sides by 3)
-3x+7<11
-3x<4
x>-4/3
So anything less than or equal to -4/3 does not belong to the solution set.
With your update:
"<span>The options is 4,-1,-5,and 0"
-5 does not belong to the solution set...</span>