Quote:
Originally Posted by Geary
2( ) means 2-of whatever is within the parenthesis. The 2 cannot be involved in any other operation in the equation. It is strictly multiplication of whatever total is within the parenthesis .. and ONLY because it lack the "x" which would separate it from the parenthesis.
While I don't have any math book on hand to prove ANY operation's sequence, I know for certain that this is a hard rule we were taught .. over & over through repetition. (Our teacher, Peter Cole, was an actual mathematician who only taught so that he could have a more flexible surfing schedule  ) |
Well my teacher told me that multiplication could be indicated in many ways
it could be 2xY, 2*Y or 2.Y or 2Y, all those are the same thing...
Hence what Bergman says
"It is interesting that in the 48/2(9+3) problem, the last element was written 9+3 rather than 12. If the latter had been used, it would have been necessary to insert a multiplication sign, 48/2×12,"
So he clearly confirms that the symbol could be used there. Once it's (9+3) has been worked down to .... 12
so 2x(9+3) = 2*(9+3)= 2.(9+3) = 2(9+3) It's 2 times whatever follows
It only works that way if it's algebra , pure numbers math, would be confusing
2 12 or 2 . 12 would not make sense, so the symbol x is required
But that wasn't the case here.. it was 2(9+3)
Not (2(9+3))
The only way you can reduce 2(9+3), is by first taking out the 9+3, making a 12 out of it
At that point the () serves no purpose anymore, andit becomes 2*12
Which is fine
Except there's still a 48/ in front of it, which has to be dealt with first.
48 / 2 * 12 is and always will be 288
And the above post, of a maths professor calling it ambigious.. He's obviously making a case for using parenthesis whenever possible so there can't be any confusion by those who don't know the rules...
And although he did not actually take sides as to the outcome having to be 2 or 288..
he did in fact confirm that the 2(9+3) = 2x12 or 2x(9+3)
And by doing so , he actually confirms that it the outcome ought to be 288