Question

find the product of (3x+2y)(3x-2y)(9x^2+4y^2)

Answer 1

$(3x + 2y)(3x - 2y)(9x {}^{2} + 4y {}^{2} ) \\ =((3x) {}^{2} - (2y) {}^{2})(9x {}^{2} + 4y {}^{2} ) \\ = (9x {}^{2} - 4y {}^{2} )(9x {}^{2} + 4y {}^{2} ) \\ =(( 9x {}^{2} ) {}^{2} -( 4y {}^{2}) {}^{2} ) \\ = 81x {}^{4} - 16y {}^{4}$

Answer 2

{(3x)²- (2y)² }( 9x² + 4y²)  =  (9x² - 4y²)(9x² +4y²) = 

⇒(9x²)² -  (4y²)²  = 81x⁴ - 16y⁴ 

hope you will get this