i need help on this hegarty question i have been stuck on for hours

The difference of the two numbers in scientific form is:
[tex]493*10^{-9} = 0.00000493[/tex]
Here we want to solve:
[tex](5*10^{-7}}) - (7*10^{-9})[/tex]
To solve this, we should have the same exponent in both sides, to get that, we can rewrite the first number as:
[tex]5*10^{-7} = 500*10^{-9}[/tex]
Replacing that, we will get:
[tex](500*10^{-9}) - (7*10^{-9}}) = 493*10^{-9}[/tex]
To write it in standard form, we need to move the decimal point 9 times to the left, so we get:
[tex]493*10^{-9} = 0.00000493[/tex]
The difference is equal to 0.00000493.
If you want to learn more about scientific notation:
https://brainly.com/question/5756316
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