Respuesta :

Answer:

9x ^2 − 25

 

Explanation:

( a + b ) ( a − b ) = a ^2 − ^b 2

substitute  a  with  3 x  and  b  with 5:

( 3 x + 5 ) ( 3 x − 5 ) = ( 3 x ) 2 −5^ 2 = 9 x ^2 − 25

( 3 x + 5 )( 3 x − 5 ) =  9 x ^2 − 25

Answer:

9x² - 25

Step-by-step explanation:

(a - b)(a + b)= a² - b²

a = 3x   ; b = 5

(3x - 5 )(3x + 5)= (3x)² - 5²

                        = 3²x² - 25

                        = 9x² - 25