Answer:
2 x 10^1
9.999 x 10^4
Explanation:
For a number to be written in Scientific Notation, it has to abide to 2 rules:
1) It has to be within 1 and 10.
2) It has to be multiplied by ten to the power of a number(x)
Ex:
1.473 x 10^7 is written in Scientific Notation
6.9 x 17^3 is not written in Scientific Notation
0.372 x 10^39 is not written in Scientific Notation
This all means that 4.38 x 5^10 and 0.641 x 10^3 are not written scientific notation, as they do not abide to all the rules of the equation to be written in Scientific Notation, meanwhile 2 x 10^1 and 9.999 x 10^4 are written in Scientific Notation, as they abide to all rules of an equation to be written in Scientific Notation.