\fWhat are the first three terms in the expansion of (x +y)" if the polynomial is written in descending order by degree of X? Select one: O a. x9 + 8x By8+ 28xly2 O b. x9 + 9xBy + 36x7y2 O c. x' y' + 8x By8+28xly O d. xy" + 9x By8+36x7y7 Which expression correctly identifies the number of terms in the expansion of (b + 3a=)"? Select one: of Oa. g-1 Ob. b+a Oc. b-a Od. g+1