Polynomial Function

Question

f(x) = 2x^4 - x^3 + 6x^2 - 7x - 5 

 

Evaluate f(3a).

Answer 1

Just replace the x with 3a then do the operations

 

f(x) = 2x⁴ - x³ + 6x² - 7x - 5

f(3a) = 2(3a)⁴ - (3a)³ + 6(3a)² - 7(3a) - 5

 

Can you finish it from here?  Hint: (3a)⁴ = 3⁴*a⁴ = 81a⁴