D) alternate exterior angles; x = 5; 116 degrees; 116 degrees
If the diagram given by derricklawrence is correct, then you will realize that the angles with expressions are alternate exterior angles, so they have the same value, which means that the equations are equal to each other. So we can create the following equality:
21x + 11 = 20x + 16
Now to solve for x. Subtract 20x from both sides, getting:
x + 11 = 16
Subtract 11 from both sides, getting:
x = 5
Now substitute the known value for X into one of the equations.
20x + 16 = d
20*5 + 16 = d
100 + 16 = d
116 = d
And of the available options, choice "D) alternate exterior angles; x = 5; 116 degrees; 116 degrees" is an exact match.
