15. convert the following values into scientific notation, a) 42,670,000 b) 0.0000008

8x10^-7

Step-by-step explanation:

First one you have correct however the second one you were close lets figure it out:

0.0000008

In order to move the decimal in front of the eight we have to "jump" 7 times to the right.  Furthermore since we have to move the decimal to the right our exponent will be negative.  That means that we have:

~~~Brainliest Appreciated~~~

Step-by-step explanation:

Let's multiply the first equation by 7 and the second equation by -2

Now add them together. In this step, x is eliminated.

Divide by 26.

Now plug this into any of the two equations to find x.