Final answer:
The value of 'r' in the expression 3²(2+7)×[3(2+1)]² when rewritten as 9r is 81. This is determined by applying the order of operations (PEMDAS/BODMAS) to simplify the expression.
Step-by-step explanation:
The expression 3²(2+7)×[3(2+1)]² can be rewritten using the order of operations (also known as PEMDAS/BODMAS). This acronym represents Parentheses/Brackets, Exponents/Orders, Multiplication and Division, and Addition and Subtraction. First, simplify the operations inside the parentheses and brackets. Then, apply the exponents. Finally, perform the multiplication.
Therefore, starting with the expression: 3²(2+7)×[3(2+1)]², we solve step by step:
- First, simplify inside the parentheses: 3²(9)×[3(3)]² which becomes 3²(9)×(9)².
- Next, apply the exponents: 9×9×81.
- Finally, perform the multiplication: 729.
Given the equation 9r = 729, you can solve for r by dividing by 9. Therefore, r = 729 / 9 = 81.
Learn more about order of operations