Question 131918
{{{(r^2-81)/(r+9)^2}}} Start with the given expression



{{{(r^2-81)/((r+9)(r+9))}}} Expand {{{(r+9)^2}}} to get {{{(r+9)(r+9)}}}



{{{((r+9)(r-9))/((r+9)(r+9))}}} Factor {{{r^2-81}}} to get {{{(r+9)(r-9)}}}



{{{(cross((r+9))(r-9))/(cross((r+9))(r+9))}}} Cancel like terms



{{{(r-9)/(r+9)}}} Simplify




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Answer:


So {{{(r^2-81)/(r+9)^2}}}  simplifies to {{{(r-9)/(r+9)}}}

In other words, {{{(r^2-81)/(r+9)^2=(r-9)/(r+9)}}}