Question

Which shows the expression below simplified?

(8 × 10-7) × 0.0007
A. 5.6 × 1028
B. 5.6 × 10-11
C. 1.5 × 1028
D. 5.6 × 10-10

Answer 1

You have 8x10^-7 and 0.0007 is the same as 7.0x10-^4

Answer 2

So simply multiply 8*7 and add together -7 -4 so you get
56.0x10^-11
since there is no answer like above, there is one that fits right if
you add +1 to the -11 which moves the dot to the left one spot,
therefore 5.6x-10^-10