perform the indicated operation, give answer in scientific notation.

(5x10^2)x(5.6x10^4)

2.8*10^7

(b-4).(b+8)

To perform the multiplication operation (5x10^2)x(5.6x10^4) and obtain the answer in scientific notation, we need to multiply the numbers and add the exponents.

Step 1: Multiply the coefficients (5 and 5.6):
5 x 5.6 = 28

Step 2: Add the exponents (10^2 and 10^4):
10^2 x 10^4 = 10^(2+4) = 10^6

So, the answer in scientific notation is 2.8 x 10^7.