Question

I'm in virtual school. And I keep getting this question wrong. Could anyone answer. and then explain how they got that answer. Appreciated. :)

Evaluate the following expression using the values given:

Find -3a2 - b3 + 3c2 - 2b3 if a = 2, b = -1, and c = 3.

Answer 1

okay so plug in the equation

Answer 2

I did. and when i submitted my answer they said it was incorrect?

Answer 3

the answer is 18

Answer 4

so it becomes\[-6(2)-3+9(2)+2(3)\]

Answer 5

hope this helps

Answer 6

\[\large -3a^2 - b^3 + 3c^2 - 2b^3\]
\[=\large -3a^2 - 3b^3 + 3c^2\]is a start

Answer 7

\[-12-3+18\]

Answer 8

is it right? @knudsona

Answer 9

the final answer is 3

Answer 10

\[=\large -3a^2 - 3b^3 + 3c^2\]
\[=\large -3\times ^2 - 3\times(-1)^3 + 3\times 3^2\]

Answer 11

http://www.wolframalpha.com/input/?i=-3a2+-+b3+%2B+3c2+-+2b3+if+a+%3D+2%2C+b+%3D+-1%2C+and+c+%3D+3.

Answer 12

I feel insanely stupid right now.

Answer 13

look at what i gave u and try it

Answer 14

why?

Answer 15

\[=\large -3\times2 ^2 - 3\times(-1)^3 + 3\times 3^2\]

Answer 16

@knudsona Why do you feel stupid

Answer 17

satelite explain urself i dont even get where your going

Answer 18

@justnick09 your answer is incorrect.

Answer 19

\[-3\times 4-3\times (-1)+3\times 9\]
\[-12+3+27\]\[-9+27=18\]

Answer 20

ohhhh those were in powers omg...

Answer 21

use these for powers 7^2

Answer 22

yeah sorry, i didnt know what t do for that. lol.

Answer 23

@satellite73 is right

Answer 24

thank you @satellite73 @theonlycool13 @justnick09

Answer 25

hey satellite how did you get what you did i don't quite follow

Answer 26

yo welcome