Question 222692


{{{64r^2-121}}} Start with the given expression.



{{{(8r)^2-121}}} Rewrite {{{64r^2}}} as {{{(8r)^2}}}.



{{{(8r)^2-(11)^2}}} Rewrite {{{121}}} as {{{(11)^2}}}.



Notice how we have a difference of squares {{{A^2-B^2}}} where in this case {{{A=8r}}} and {{{B=11}}}.



So let's use the difference of squares formula {{{A^2-B^2=(A+B)(A-B)}}} to factor the expression:



{{{A^2-B^2=(A+B)(A-B)}}} Start with the difference of squares formula.



{{{(8r)^2-(11)^2=(8r+11)(8r-11)}}} Plug in {{{A=8r}}} and {{{B=11}}}.



So this shows us that {{{64r^2-121}}} factors to {{{(8r+11)(8r-11)}}}.



In other words {{{64r^2-121=(8r+11)(8r-11)}}}.