Question

Simplify the expression. Write the answer using scientific notation.

(9 x 10^7) (7 x 10^9)

Answer 1

You always use the same method for this kind of problem.
Step one: regroup your multiplicators (9 and 7 in your case)
Step two: regroup your powers of 10 (10^7 and 10^9)

so, you get:
9*7=63
10^7*10^9=10^16 (simply add the exponents)

In scientifical notation, we don't want numbers such as 63... it's too big! But, we know that 63=6,3*10^1, so, we repeat the same process we just did :

6,3*10^1*10^16=6,3*10^17

Is this clear?

Answer 2

yes(: