130 likes | 251 Views
PROBLEM SOLVING: FORM WORDS TO SYMBLOS. LESSON1.1. Keywords that indicate operations used in writing algebraic expressions. Keywords that indicate operations used in writing algebraic expressions. How to represent a word expression by algebraic symbols.
E N D
PROBLEM SOLVING:FORM WORDS TO SYMBLOS LESSON1.1
Keywords that indicate operations used in writing algebraic expressions.
Keywords that indicate operations used in writing algebraic expressions.
How to represent a word expression by algebraic symbols. • First choose a variable to represent the unknowns. • Identify the key word(s) that indicate the operation. • Use algebraic symbols to represent the word expression.
Example 1. Write an algebraic expression for each word expression. • P29.50 less than the cost of a coat • Solution: • Let x = the cost of the coat. • P29.50 less than the cost : x – 29.50
Example 2. Write an algebraic expression for each word expression. • Five more than three times the number of pages • Solution: • Let p = the number of pages. • Five more than three times the number : 3p+5
Many word problems involve more than one unknown . • In these problems, one condition (CONDITION1) tells how the unknowns related. • You can use this condition to represent the unknowns. • A second condition (CONDITION 2) tells what quantities are equal. • You can use this condition to write an equation for the problem.
Example 3. • In a recent year, the cost of electricity used for lighting a house was P9.00 less than 6 times the cost of operating a color tv set (CONDITION1). The total cost for these two items was P834.50 (CONDITION 2). Find the cost for lighting.
Solution • Use CONDITION1 to represent the unknowns. • Let c = the cost of operating a color tv set . • Then 6c - 9=the cost for lighting.
Solution • Check: • CONDITION 1. Is the cost for lighting P9.00 less than 6 times the cost for the color tv? • 614.00 =6(P120 – P9.00? • Yes. • Use CONDITION 2 to write an equation. • c + 6c - 9=834.50 total cost • Solve the equation: • c + 6c - 9= 834.50 • 7c -9 = 834.50 • 7c = 843.50 • c = 120.50 • 6c – 9 = 614.00
Solution • Check: • CONDITION 2. Is the total cost P834.50? • P614.00 + P120 = P834.50? • Yes. • Use CONDITION 2 to write an equation. • c + 6c - 9=834.50 total cost • Solve the equation: • c + 6c - 9= 834.50 • 7c -9 = 834.50 • 7c = 843.50 • c = 120.50 • 6c – 9 = 614.00
STEPS IN SOLVING WORD PROBLEMS. • Identify CONDITION1.Use this condition to represent the unknowns. • Identify CONDITION2. Use this condition to write an equation for the problem. • Solve the equation. • Check in the original conditions of the problem. Answer the question.