What is the product? (9t − 4)(−9t − 4) −81t2 − 16 −81t2 16 −81t2 − 72t 16 −81t2 72t 16

We have to find the product : ( 9 t - 4 ) ( - 9 t - 4 ) = - ( 9 t - 4 ) ( 9 t + 4 ) After that we can use the difference of squares. The formula is: ( a + b ) ( a - b ) = a^2 - b^2. In this case: - ( 9 t - 4 ) ( 9 t + 4 ) = - ( 81 t^2 - 16 ) = - 81 t^2 + 16 . B ) - 81 t^2 + 16.