ShmoopTube

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And here's your shmoop du jour.

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Evaluate the expression 3x3 - 4y-2 for  x = 3 and y = 2.

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Here are the potential answers...

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Before we spoil the ending, hit pause and try it yourself.

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Can we plug in numbers? Yes we can.

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If we substitute 3 as x and 2 as y, we can

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rewrite the equation as 3 times 3 cubed minus 4 times 2 to the negative second...

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3 cubed is 27... and 3 times 27 is 81 and we're done with the first part

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Now for the y's.

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Don't forget that little negative sign next to the 2 in the exponent.

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Remember that negative exponents basically just mean "1 over"...

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...so we can move the y squared into the denominator...

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...and rewrite that second part as 4 over 2 squared. 2 squared is 4. 4 over 4 is 1.

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We subtract one from 81 and we get 80. Answer: D

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Plugging has never been more fun.

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