SOLUTION: If x= -1 and y= 2, What is the value of the expression 2x^3 - 3xy
I have tried 2(-1)^3-3(-1)(2)
2(-3) - -3(2)
-6 - -6
answer 0
Algebra.Com
Question 423106: If x= -1 and y= 2, What is the value of the expression 2x^3 - 3xy
I have tried 2(-1)^3-3(-1)(2)
2(-3) - -3(2)
-6 - -6
answer 0
I have an answer sheet and it says the answer is 4. I can not, to save my life figure out how they came up with 4. PLEASE HELP!!!!
Answer by jim_thompson5910(35256) (Show Source): You can put this solution on YOUR website!
2x^3 - 3xy
2(-1)^3 - 3(-1)(2)
2(-1) - 3(-1)(2) .... this is where you made the mistake (-1)^3 = -1 NOT -3
2(-1) - 3(-2)
-2 - (-6)
-2 + 6
4
So 2x^3 - 3xy = 4 if x = -1 and y = 2
If you need more help, email me at jim_thompson5910@hotmail.com
Also, please consider visiting my website: http://www.freewebs.com/jimthompson5910/home.html and making a donation. Thank you
Jim
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