Express (1.4 x 10^7) (2.5 x 10^2) In Scientific Notation.?

Answer #1 works fine when the product of the two numbers still remains in the range between 1 and 10.

If I change the problem to:

(5.5 * 10^7) (2.5 * 10^2)

you get the following:

13.75 * 10^9

Since this is no longer in scientific notation, you have to move the decimal over one more to make it qualify:

1.375 * 10^10

(1.4 x 10^7)(2.5 x 10^2)
= (1.4 x 2.5) x (10^7 x 10^2)
= (3.5) x [10^(7 + 2)]
= (3.5) x [10^9]
= 3.5 x 10^9
(answer A)

A
(1.4 x 10^7) (2.5 x 10^2)
(1.4 *2.5 )x 10^9
3.5 x 10^9

a.
just add the exponents and multiply 1.4 and 2.5