What expression is equivalent to 10x2y+25x2

Which function has the same domain as y=2x

What is the missing reason in step 5? linear pair postulategivendefinition of complementary anglescongruent complements theorem

The domain of a function can be represented by which one of the following options? o a. a set of output values o b. a set of f(x) values o c. a set of input values o d. a set of both input and output values