Answer:
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Step-by-step explanation:
Steps:

Subtract 4 from both sides:

Simplify:

Divide both sides by 12:

Simplify:

Point Form:
(2, 4), (1, 1)
Equation Form:
x = 2, y = 4
x = 1, y = 1
X is 7 and y is 2 I am pretty sure
Given parameters:
Cost price of the article = Nu.28.30
Selling price of the article = Nu.29.30
Unknown:
Gain percentage = ?
The gain percentage is the same as the percentage profit on a trade.
The formula is given as:
Gain percentage = 
Profit = Selling price - Cost price
= Nu.29.30 - Nu.28.30
= Nu. 1
Now input the parameters and solve;
Gain percentage = 
= 3.5%
The gain percent is 3.5%