f(x)=2× squared -x cubed.Evaluate f (-3)

Question

f(x)=2 squared -x cubed.Evaluate f(-3)

Answer 1

Hello.

Let me make sure I am interpreting the question correctly. I am reading: f(x) = 2x² - x³. If this is right, all you have to do is plug in -3 to the equation. So, everywhere you see an x, replace it with a (-3). 

 

f(x) = 2x² - x³

 

f(-3) = 2(-3)² - (-3)³ [plug in (-3)]

 

f(-3) = 2(9) - (-27) [evaluate. (-3)² = 9 and (-3)³ = -27]

 

f(-3) = 18 + 27 [reduce]

 

f(-3) = 45 [add]

 

Hopefully, this helps you out. If that is not the right set up, it is still the same process. Just plug in negative three and be careful with the negative signs. 

 

Frank

 

Answer 2

f(-3) = 2(-3)² - (-3)³

f(-3) = 2(9) - (-27)

f(-3) = 18 + 27

f(-3) = 45

Answer 3

f(x) = 2x² - x³

f(3) = 2(-3)² - (-3)³

f(3) = 18 + 27