Answer:
7/4
Step-by-step explanation:
Completing the square follows the principle of taking

and converting it into

where d is the 'correctional number' as I like to call it - i.e. the number that converts the expanded bracket into the +c, since the expanded bracket will give us

.
In this case, 2/2=1 so we have the first part:

.
Expanding this gives us

. We need c to be 9, so we can just add 8.
Putting this together:

Now we can solve it more easily.
Rearranging:
LCD is 20
3/5 -> 12/20
1/20 -> 1/20
1. Put all values in decimals
0.222=0.222
1/5= 0.2
0.02= 0.02
2. Order the cakes from least to greatest
0.02, 0.2, 0.222
Hope this helps!
To find the total multiply the sale price by 1 + tax rate.
Total = 20 x 1.05
Total = $21.00