Answer:
Complementary angles.
Step-by-step explanation:
Notice that 
and 
, by given.
, by sum of angles.
, by supplementary angles definition.
Which means,
Therefore,
, in other words, angles a and b are complementary by definition.
For #16, every input by +1 has an output of +7.
9 + 7 = 16
16 + 7 = 23
23 + 7 = 30.....
The answer for this questions would be: D. 120
Like terms: in the case of exponents, the same exponents for different numbers
Like 7x and 8x are like terms.
5x and 6x^2 would be unlike terms
Get it??
Good luck~~
