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Chapter 3

1st Degree Polynomial Equations


3.5 Problems that can be solved with the help of polynomial equations of the 1st degree.

    In order to solve a problem with the help of equations we work as following

Example 1

The price of a product increased 20%  the  first year and 25% the following year. The final price is £930.
What was the starting price of the product? 

Lets name x the starting price of the product. The first year the price increased 20% and it became:
x + (20/100)x = x + (1/5)x = 6x/5
The following year it increased 25% and it became:
6x/5 + (25/100)(6x/5) = 6x/5 + 3x/10 =15x/10=3x/2
Finally we have the equation
3x/2 = 9303x=2*930x=(2*930)/3x=620

So, the starting price of the product was £620.

 Exercise 1

The age of a father is three times bigger than the age of his son. After 12 years the age of the father is going to be double the age of the son. What are the ages of the father and son today?