Question 132303


{{{(3-7x^9)^2}}} Start with the given expression



{{{(3-7x^9)(3-7x^9)}}} Expand. Remember something like {{{x^2=x*x}}}



Now let's FOIL the expression




Remember, when you FOIL an expression, you follow this procedure:



{{{(highlight(3)-7x^9)(highlight(3)-7x^9)}}} Multiply the First terms:{{{(3)*(3)=9}}}



{{{(highlight(3)-7x^9)(3+highlight(-7x^9))}}} Multiply the Outer terms:{{{(3)*(-7x^9)=-21x^9}}}



{{{(3+highlight(-7x^9))(highlight(3)-7x^9)}}} Multiply the Inner terms:{{{(-7x^9)*(3)=-21x^9}}}



{{{(3+highlight(-7x^9))(3+highlight(-7x^9))}}} Multiply the Last terms:{{{(-7x^9)*(-7x^9)=49x^18}}}



{{{9-21x^9-21x^9+49x^18}}} Now collect every term to make a single expression




{{{49x^18-42x^9+9}}} Now combine like terms



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Answer:

So {{{(3-7x^9)^2}}} foils and simplifies to  {{{49x^18-42x^9+9}}}


In other words, {{{(3-7x^9)^2=49x^18-42x^9+9}}}