Option 2.
1. Simplify 7 + (12 - 9) + 7 × 3(8 - 5)
According to the Order of Operations, contents of parentheses are evaluated first. This gives
... 7 + 3 + 7 × 3 × 3
Then multiplication and division are performed left to right.
... = 7 + 3 + 21 × 3
... = 7 + 3 + 63
Followed by addition and subtraction left to right.
... = 10 + 63
... = 73
A Google search box can be relied upon to do the operations in the correct order.
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2. When the expression is rewritten, a different result is obtained. This is because the operations indicated by the second set of parentheses are altered.
... (7 + 12) - 9 + (7 × 3)8 - 5
... = 19 - 9 + 21 × 8 - 5
... = 19 - 9 + 168 - 5
... = 10 + 168 - 5
... = 178 - 5
... = 173
In the first expression, both +8 and -5 are multiplied by 21. In the rewritten expression, only +8 is multiplied by 21.