Order of operations doubt on this expression

In summary, the order of operations for solving an expression is PEMDAS, which stands for Parentheses, Exponents, Multiplication and Division (from left to right), and Addition and Subtraction (from left to right). This is a mathematical convention that must be followed in order to get the correct answer. If the expression contains both parentheses and exponents, you should simplify the expression inside the parentheses first, then solve any exponents, and continue with the rest of the operations according to the order of operations. Parentheses are not always necessary in an expression, but they can be used to clarify the order of operations. Alternative acronyms such as BEDMAS or BODMAS can also be used as long as the correct order is
  • #1
mathlearn
331
0
Let's say that we have this expression,

$\frac{1}{2}*2x*x-2$

So now solving this in one method we can

$\frac{1}{\cancel 2}*\cancel2x*x-2=x^2-2$

In another way

$\frac{1}{2}*2x*x-2=\frac{2x^2-2}{2}=x^2-1$

What is the reason that I get two different answers ? I hope that both ways are valid

Many THanks :)
 
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  • #2
The order of operations dictates that we do multiplication/division first before subtraction, so the first method is correct. The second method you used would be valid if we had:

\(\displaystyle \frac{1}{2}(2x\cdot x-2)\)
 

FAQ: Order of operations doubt on this expression

What is the order of operations for solving an expression?

The order of operations, also known as PEMDAS, stands for Parentheses, Exponents, Multiplication and Division (from left to right), and Addition and Subtraction (from left to right).

Can I change the order of operations when solving an expression?

No, the order of operations is a mathematical convention that must be followed in order to get the correct answer. Changing the order may result in an incorrect solution.

What should I do if the expression contains both parentheses and exponents?

You should first simplify the expression inside the parentheses, then solve any exponents, and finally continue with the rest of the operations according to the order of operations.

Do I need to always use parentheses in an expression?

No, parentheses are only necessary if they are explicitly stated in the expression or if you want to clarify the order of operations. If there are no parentheses, you can follow the order of operations as usual.

Can I use a different acronym for remembering the order of operations?

Yes, there are alternative acronyms such as BEDMAS (Brackets, Exponents, Division and Multiplication, Addition and Subtraction) or BODMAS (Brackets, Orders, Division and Multiplication, Addition and Subtraction). As long as you follow the correct order, any acronym can be used.

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