- Translating English into algebra:
1) Assign variables
- Try to minimize the number of variables
- Make use of a relationship given in the problem.
2) Write equations
3) Solve algebraically
4) Evaluate the algebraic solution in the context of the problem - make sure you answer the question asked - You can check your translations with easy numbers.
- Write an unknown percent as a variable divided by 100
- Translate bulk discounts and similar relationships carefully
- When a problem involves several quantities and multiple relationships, it is often a good idea to make a chart or a table to organize the information, i.e. age problems:
- Put people in rows and times in columns.
- Use variables to indicate the age of each person now, fill other columns by adding or subtracting time from the now column.
- Write equations that relate the individuals' ages together - In a typical Price-Quantity problem, you have two relationships:
- the quantities sum to a total
- the monetary values sum to a total - Look out for hidden constraints (i.e. whole number, positive)
- Think about what is being measured or counted and whether a hidden constraint applies.
- To solve algebra problems that have integer constraints, test possible values systematically in a table.
- When all quantities are positive in a problem, certain algebraic manipulations are safe to perform: 1) dropping negative solutions of equations; 2) dropping negative possibilities with inequalities (see MGMAT WT p21)
Wednesday, December 2, 2009
Algebraic Translations
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