Write the expression as a polynomial

Question

Write the expression as a polynomial: (5-2a+a²)(4a²-3a-1)

Answer 1

4a^4 -11a^3 +25a^2 -5

a^2 x 4a^2 = 4a^4

a^2 x (-3a) = -3a^3

4a^2 x (-2a) = -8a^3

-3a^3 - 8a^3 = -11a^3

2a x -3a=-6a^2

a^2 x -1 = -a^2

4a^2 x5 = 20a^2

sum those 3 to get 25a^2

5 x -1 = -5 for the constant term