logo for solving-math-problems.com
leftimage for solving-math-problems.com

where would the "parentheses" be?











































what do i do first in this problem:

-x^2

do I multiply by the negative or square the x?

Comments for where would the "parentheses" be?

Click here to add your own comments

Oct 25, 2011
Where would the parentheses be?
by: Staff


Question:


what do i do first in this problem:

-x^2

do I multiply by the negative or square the x?



Answer:

-x²

= -(x²)

How do you know this is true?


The PEMDAS order of operations answers this question.

PEMDAS order tells you what to do first, second, . . . etc.


PEMDAS stands for: parentheses, exponents, multiplication, division, addition, subtraction


Step 1: evaluate PARENTHESES

PEMDAS order of evaluation: PARENTHESES, exponents, multiplication, division, addition, subtraction

There are no expressions enclosed in parentheses


Step 2: evaluate EXPONENTS


PEMDAS order of evaluation: parentheses, EXPONENTS, multiplication, division, addition, subtraction




Step 3: MULTIPLICATION


PEMDAS order of evaluation: parentheses, exponents, MULTIPLICATION, division, addition, subtraction

-x²

= -1 * x²

= -x²

-----------------------------------------------------

A final note:

Still not convinced?

You can VERIFY the solution with a CALCULATOR.

. . . but, not an ordinary (basic) calculator.

Substitute any number, such as a 3, for x

-x²

-3²

To compute -3², you should use a “SMART” CALCULATOR.

A "Smart" Calculator (Formula Calculator) automatically takes into account PEMDAS order. The person using the calculator does not need to be concerned about which numbers to evaluate 1st, 2nd, 3rd, etc.

This is not what most people use. Most people use a basic calculator. Basic calculators are inexpensive (as low as $1) and plentiful (you can buy one at any drugstore or supermarket).

I call basic calculators “dumb calculators” because they rely on the person using the calculator to input the numbers in PEMDAS order. If the person using the calculator inputs the numbers incorrectly, a basic calculator will give an incorrect answer.

You can download a FREE SMART CALCULATOR at:

http://www.zoesoft.com/console-calculator/


If you decide to check the work for this example problem using a smart calculator, input the entire expression exactly as follows:

-3^2 (instead of –x^2)

The answer will be -9

You will see that a smart calculator it will automatically calculate the proper answer using the correct PEMDAS order.

You still need to know and understand how PEMDAS works because you will use variables (instead of numbers) in your classes. However, a smart calculator will help you check your work when you evaluate numerical expressions.






Thanks for writing.

Staff
www.solving-math-problems.com


Click here to add your own comments

Join in and write your own page! It's easy to do. How? Simply click here to return to Math Questions & Comments - 01.



Copyright © 2008-2015. All rights reserved. Solving-Math-Problems.com