8+2k=4k+4
8-4=4k-2k I placed the like terms on each side.
4=2k Simplify
4/2=k Leave the variable a side
2 = k
Hi there!
All you need to do to solve for a is add 1.6 to both sides of the equation.
It will look like this:
a - 1.6 + 1.6 = -3.7 + 1.6
After this you will see that a = -2.1.
Hope this helps!
When in doubt just replace a with -2.1 and see if you still get -3.7. :)
Answer:

Step-by-step explanation:
Total number of toll-free area codes = 6
A complete number will be of the form:
800-abc-defg
Where abcdefg can be any 7 numbers from 0 to 9. This holds true for all the 6 area codes.
Finding the possible toll free numbers for one area code and multiplying that by 6 will give use the total number of toll free numbers for all 6 area codes.
Considering: 800-abc-defg
The first number "a" can take any digit from 0 to 9. So there are 10 possibilities for this place. Similarly, the second number can take any digit from 0 to 9, so there are 10 possibilities for this place as well and same goes for all the 7 numbers.
Since, there are 10 possibilities for each of the 7 places, according to the fundamental principle of counting, the total possible toll free numbers for one area code would be:
Possible toll free numbers for 1 area code = 10 x 10 x 10 x 10 x 10 x 10 x 10 = 
Since, there are 6 toll-free are codes in total, the total number of toll-free numbers for all 6 area codes = 
<span>a) if the bacteria double every hour then it would 2^t(1200) where t is hours and 1200 is the amount in there to begin with.
b) assuming the formula is correct it would be 2^24(1200). this becomes 20132659200 total in a day.</span>
The answer is 200,000 + 80,000 + 3,000 + 900 +80.
HOPE IT HELPS ♥️