Do you mean how you can tell between an area formula and a volume formula? Well usually like on a reference sheet it says the shape and the letter a or v, a representing area and v representing volume. I hope this helps, if it doesn't please tell me in the comment section
-converting to a common denominator
The terms -c of the left side was converted to -4ac/4a to have the same denominator of b^2/4a.
Repost your question. Unclear as typed.
Answer:
Profit % = 39%
Step-by-step explanation:
Cost price of the article = 9
Price for repairing = 4
Therefore, Total cost of the article = 9 + 4 = 13
Selling price of the article = 18
Profit = 18 - 13 = 5
Hence,


Profit percent (to the nearest %) = 39%