HELP TIMED BRAINLIST QUICK

12 x^9 + 15 x^8 - 8 x^6 - 10 x^5 = A.) is the answer

Step-by-step explanation:

Expand the following:

x^4 (3 x^3 - 2) (4 x^2 + 5 x)

Hint: | Multiply 3 x^3 - 2 and 4 x^2 + 5 x together using FOIL.

(3 x^3 - 2) (4 x^2 + 5 x) = (3 x^3) (4 x^2) + (3 x^3) (5 x) + (-2) (4 x^2) + (-2) (5 x) = 12 x^5 + 15 x^4 - 8 x^2 - 10 x = 12 x^5 + 15 x^4 - 8 x^2 - 10 x:

x^4 12 x^5 + 15 x^4 - 8 x^2 - 10 x

Hint: | Distribute x^4 over 12 x^5 + 15 x^4 - 8 x^2 - 10 x.

x^4 (12 x^5 + 15 x^4 - 8 x^2 - 10 x) = x^4 (12 x^5) + x^4 (15 x^4) + x^4 (-8 x^2) + x^4 (-10 x):

12 x^4 x^5 + 15 x^4 x^4 - 8 x^4 x^2 - 10 x^4 x

Hint: | Combine products of like terms.

x^4 (-10) x = x^(4 + 1) (-10):

12 x^4 x^5 + 15 x^4 x^4 - 8 x^4 x^2 + -10 x^5

Hint: | Evaluate 4 + 1.

4 + 1 = 5:

12 x^4 x^5 + 15 x^4 x^4 - 8 x^4 x^2 - 10 x^5

Hint: | Combine products of like terms.

x^4 (-8) x^2 = x^(4 + 2) (-8):

12 x^4 x^5 + 15 x^4 x^4 + -8 x^6 - 10 x^5

Hint: | Evaluate 4 + 2.

4 + 2 = 6:

12 x^4 x^5 + 15 x^4 x^4 - 8 x^6 - 10 x^5

Hint: | Combine products of like terms.

x^4×15 x^4 = 15 x^8:

12 x^4 x^5 + 15 x^8 - 8 x^6 - 10 x^5

Hint: | Combine products of like terms.

x^4×12 x^5 = x^(4 + 5)×12:

12 x^9 + 15 x^8 - 8 x^6 - 10 x^5

Hint: | Evaluate 4 + 5.

4 + 5 = 9:

12 x^9 + 15 x^8 - 8 x^6 - 10 x^5

  n=   0.0000 - 0.3750 i  

  n=   0.0000 + 0.3750 i

step-by-step explanation:

one of these should be correct