Half a book each month!!! have a good day!
Answer:
see below
Step-by-step explanation:
Scientific notation is a * 10 ^b
a must be a number between 1 ( including 1 ) and less than 10
12 is greater than 10 so it is not scientific notation
Let's call:
a = price of 1 apple
p = price of 1 peach
The total cost is the price of 1 apple times the number of apples plus the price of 1 peach times the number of peaches, therefore the system can be:

Solve for a in the second equation (you can choose to solve for any of the variables in any of the equations, try to understand what is the best):
a = (4.82 - 5p) / 4
Now, substitute in the first equation:
6 · (4.82 - 5p) / 4 + 9p = 7.86
7.23 - (15/2)p + 9p = 7.86
(3/2)p = 0.63
p = 0.42
Now, substitute this value in the formula found for a:
<span>a = (4.82 - 5·0.42) / 4</span>
= 0.68
Therefore, one apple costs
0.68$ and one peach costs
0.42$.