Question 112672
{{{a(a+5)(a-5)}}} Start with the given expression



{{{(a^2+5a)(a-5)}}} Distribute




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



Multiply the First terms:{{{(a^2)*(a)=a^3}}}



Multiply the Outer terms:{{{(a^2)*(-5)=-5a^2}}}



Multiply the Inner terms:{{{(5a)*(a)=5a^2}}}



Multiply the Last terms:{{{(5a)*(-5)=-25a}}}



{{{a^3-5a^2+5a^2-25a}}} Now collect every term to make a single expression




{{{a^3-25a}}} Now combine like terms



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Answer:

So {{{(a^2+5a)(a-5)}}} foils and simplifies to  {{{a^3-25a}}}


In other words, {{{(a^2+5a)(a-5)=a^3-25a}}}


Notice how  {{{a^3-25a}}} factors back to the original expression {{{(a^2+5a)(a-5)}}} (if you need help with factoring, check out this <a href="http://www.algebra.com/algebra/homework/Polynomials-and-rational-expressions/change-this-name4450.solver">solver</a>). So this verifies our answer.