Someone help me with these two questions yuh 20 points

Classify each polynomial by its degree and by its number of terms.

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

Sundar used linear combination to solve the system of equations shown. he did so by multiplying the first equation by 5 and the second equation by another number to eliminate the y-terms. what number did sundar multiply the second equation by? 2x+9y=41 3x+5y=36