college algebra help

Question

Let M(x)=-x^3+5x^2-2x+1. Find M(-2). 

M(-2)=___. (Simplify your answer.)

Answer 1

Hello, thank you for taking the time to post your question!

To solve this one you want to plug in x = -2 back into the M(x) expression

-(-2)^3 + 5(-2)^2 – 2(-2) + 1

= -(-8) + 5(4) + 4 + 1

= 8 + 20 + 4 + 1

= 33

I hope that helps you get moving in a better direction on this type of question! Feel free to reach out if you have any additional questions beyond that :)

Answer 2

We are given the value for x, so let's put that in:

(-3)³ + 5(-3)² - 2(-3) + 1

Order of operations tell us exponentials first:

-3 * -3 * -3 = -27

-3 * -3 = 9

So our problem now looks like:

-27 + 5 * 9 - 2 * -3 + 1

 

Next comes multiplication/division:

5 * 9 = 45

-2 * -3 = 6

Now it looks like:

 

-27 + 45 + 6 +1

Now addition/subtraction:

-27 + 6 + 1 = -20

-20 + 45 = 25

 

So M(-2) is 25