12.07.2015 Views

Math 017 Materials With Exercises

Math 017 Materials With Exercises

Math 017 Materials With Exercises

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

Lesson 2__________________________________________________________________________________Topics: Algebraic expressions and their evaluations; Order of operations.__________________________________________________________________________________Recall the order of operations.The order of operationsWhen evaluating arithmetic expressions, the order of operations is1) Perform all operations in parentheses first.2) Do any work with exponents.3) Perform all multiplications and divisions, working from left to right.4) Perform all additions and subtractions, working from left to right.If a numerical expression includes a fraction bar, perform all calculations above and belowthe fraction bar before dividing the top by the bottom number.Let x be an unknown number. If we increase the number by 1, the resulting number can berepresented by x 1. Now, suppose that after adding 1, we multiply some other number, called y , bythe result of the addition. We may now write the expression y ( x 1). Let us analyze why we mustplace parentheses around x 1. If an algebraic expression involves more than one mathematicaloperation, then the order of operations is followed. Thus, if we simply write yx 1(without usingparentheses), we would only be multiplying y and x, rather than y times the entire quantity x 1.According to the order of operations, using parentheses in y ( x 1)indicates that we add 1 to x first,and then multiply the result by y. Expressions yx 1and y ( x 1)have entirely different meanings,and only y ( x 1)correctly represents the result of operations performed in this example.The order of operations is used when algebraic expressions are evaluated.2For example, let us evaluate 2 x x when x 3.2 x 2 x replace each x with 3223 3 raise 3 to the second power2 9 3 multiply it by 218 3 subtract 3 from the result15Example 2.1 Rewrite the following expressions and circle the arithmetic operation together with itsoperands that has to be performed first. Write the name of the operation next to yourexpression.4a) 3 5yb) 2xSolution:15

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!