Question

Which is equivalent to this expression (z+6)(2z^2+3z+5)

a.) z^3+15z^2+23z+30
b.) 2z^3+67z+30
c.) 2z^3+15z^2+23z+30
d.) z^2+ 67z+30

Answer 1

(z + 6)(2z^2 + 3z + 5) = z(2z^2 + 3z + 5) + 6(2z^2 + 3z + 5) = 2z^3 + 3z^2 + 5z + 12z^2 + 18z + 30 = 2z^3 + 15z^2 + 23z + 30