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1 vote
Evaluate 5x^3 + 2 for x = -1.

User Kingsly
by
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2 Answers

1 vote
Assuming we are applying -1 to 5x^3 + 2...


5\left(-1\right)^3+2 \ \textgreater \ \mathrm{Follow\:the\:PEMDAS\:order\:of\:operations}


\left(-a\right)^n=-a^n,\:\mathrm{if\:}n\mathrm{\:is\:odd} \ \textgreater \ \left(-1\right)^3=-1^3=-1 \ \textgreater \ 5\left(-1\right)+2


\mathrm{Apply\:rule\:}a\cdot \left(-b\right)\:=\:-a\cdot \:b \ \textgreater \ 5\left(-1\right)=-5\cdot \:1=-5 \ \textgreater \ -5+2


-5+2=-3

Therefore -3 is our answer.

Hope this helps!
User Rbanffy
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3 votes


\huge\text{Hey there!}


\mathsf{5x^3 + 2}\\\mathsf{= 5(-1)^3+2}\\\\\mathsf{(-1)^3}\\\mathsf{= -1*-1*-1}\\\mathsf{=1*-1}\\\mathsf{= \bf -1}\\\\\mathsf{= 5(-1) + 2}\\\\\mathsf{5(-1)}\\\mathsf{= \bf -5}\\\\\mathsf{= -5 + 2}\\\mathsf{=\bf -3}\\\\\\\\\boxed{\boxed{\huge\text{Therefore, your answer is: \bf -3}}}\huge\checkmark\\\\\\\\\huge\text{Good luck on your assignment \& enjoy your day!}\\\\\\\frak{Amphitrite1040:)}

User Terry Bu
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8.2k points