You can put this solution on YOUR website!
If all you need is one solution (there are infinitely many), then all you need to do is...
Find the inverse tan of each side:
tan-1() = tan-1(-11)
The left side simplies and the calculator will give us an number for the right side: = -84.8 (degrees, rounded-off)
Now subtract 7 from each side: = -91.8 (degrees, rounded-off)
And divide by two: = -45.9 (degrees, rounded-off)
All the other solutions will be multiples of 180 (since the period of tan is 180) away from -45.9.
In response to the question in your "Thank you" note:
To turn -45.9 into radians:
If this is not the answer provided, then try adding various multiples of (since the period of tan, in radians, is ) until you get the answer. For example:
If the "official" answer does not have in it, then replace with 3.141529 (or some rounded-off version of this decimal).