Answer:
see below
Explanation:
Use the distributive property:
(y^2 +3y +7)(8y^2 +y +1)
= y^2(8y^2 +y +1) +3y(8y^2 +y +1) +7(8y^2 +y +1)
= 8y^4 +y^3 +y^2 + 24y^3 +3y^2 +3y + 56y^2 +7y +7
= 8y^4 +y^3(1 +24) +y^2(1 +3 +56) +y(3 +7) +7
= 8y^4 +25y^3 +60y^2 +10y +7 . . . . . matches the last choice