What is #(9\times 10^ { - 6} ) - ( 5\times 10^ { - 6} )#?

1 Answer
Oct 18, 2016

#4xx10^-6#

Explanation:

The question "What is #9x - 5x# " would pose no problem at all!

We can only add or subtract like terms, which is exactly what we have, so we can write:

#9x-5x = 4x#

In this case we have #9color(red)(xx10^-6) - 5 color(red)(xx10^-6)#

Although they are numbers, we can regard them as being like terms in exactly the same way as we did with the algebra.

#9# somethings - #5# somethings gives #4# somethings, as long as the 'somethings' are the same.

#9color(red)(xx10^-6) - 5 color(red)(xx10^-6) = 4 xxcolor(red)(10^-6)#