Which number is written in scientific notation? a) 7.8 x 10^-5 b) 3.4 x 100^2 c) 0.84 x 10^6 d) -5 x 10^-12

I would say A. 7.8 x 10^-5

Step-by-step explanation:

7.8 x 10^-5 can also be written as 7.8 times 10 to the negative fifth power or the exponent of negative five. But, if you solve it you would get 0.000078 as the real number.

where's the diagrams?