Simplify `(13x - 9y) (13x + 9y)`.

1.	Simplify `(13x - 9y) (13x + 9y)`.
Answer» Here , a = 13 x and b = 9y , by using the identify `(a + b) (a-b) = a^(2) - b^(2)` , we have `(13x + 9y) (13x - 9y)` . = `(13x)^(2) - (9y)^(2) = 169x^(2) - 81y^(2)`

Discussion

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