ANSWER:
For the first picture, it is the first answer. This is because of the Exterior Angle Theorem.
For the second picture, use the Exterior Angle Theorem again, but this time, solve for x.

The m∡B = 39°
The answer to 2 1/3 - 2/3 is 1 2/3
The variables are: x, y
The constant is: 4
The coefficients are: 5, 3
The exponent is: y^2