Question 557541


{{{(x+9)^2}}} Start with the given expression.



{{{(x+9)(x+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(x)+9)(highlight(x)+9)}}} Multiply the <font color="red">F</font>irst terms:{{{(x)*(x)=x^2}}}.



{{{(highlight(x)+9)(x+highlight(9))}}} Multiply the <font color="red">O</font>uter terms:{{{(x)*(9)=9*x}}}.



{{{(x+highlight(9))(highlight(x)+9)}}} Multiply the <font color="red">I</font>nner terms:{{{(9)*(x)=9*x}}}.



{{{(x+highlight(9))(x+highlight(9))}}} Multiply the <font color="red">L</font>ast terms:{{{(9)*(9)=81}}}.



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So we have the terms: {{{x^2}}}, {{{9*x}}}, {{{9*x}}}, {{{81}}} 



{{{x^2+9*x+9*x+81}}} Now add every term listed above to make a single expression.



{{{x^2+18x+81}}} Now combine like terms.



So {{{(x+9)^2}}} FOILs to {{{x^2+18x+81}}}.



In other words, {{{(x+9)^2=x^2+18x+81}}}.