Answer:
A) 1.3*10¹
B)7*10⁰ - Actually I am not very sure if it is required to write 10⁰. I normally don't write 10⁰ (When I solve problems in physics if the answer for example is 7 I just write 7 not 7*10⁰). But if you check on Google 10⁰ has been mentioned
C)1.4*10¹
D)1.2*10¹
Explanation:
For any number when you express it in a scientific notation, You should make sure that the number (for example : X) X which is going to be multiplied with a power of 10 (for example:10³,10⁴10¹⁰ etc), X should be between 1 and 10
This might sound very complicated so I can give you an example to simplify
Let's take 1.3*10¹
In this case X is 1.3
This means X*10¹
The number X is being multiplied with the power of 10(example:10¹,10²,10⁰,10⁹ ,etc) .In the above case X is being multiplied with 10¹.
Now this number X should be between 1 and 10.(Including 1)
Scientific notation= X*power of 10
where x>=1 & x<10
That is the explanation
Hope it helps
If you think my explanation is a bit complicated
you can ask me again