Question 153260
Do you want to factor this?




{{{4x^2-81}}} Start with the given expression.



{{{(2x)^2-81}}} Rewrite {{{4x^2}}} as {{{(2x)^2}}}.



{{{(2x)^2-(9)^2}}} Rewrite {{{81}}} as {{{(9)^2}}}.



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



{{{(2x+9)(2x-9)}}} Factor the expression using the difference of squares.



So {{{4x^2-81}}} factors to {{{(2x+9)(2x-9)}}}.



In other words {{{4x^2-81=(2x+9)(2x-9)}}}.