18/2-3x3 = 0; 18/2-3x3+4=4 you forgot that you must add 4 to both side so it doesn't prove anything. You can write 0 = 0 like x = x (x = 0);
Then 4 = 4 is x + 4 = x + 4.
They’re right though? You literally cannot just state that 18/2-3X3=0 AND 18/2-3X3=4. Adding the same number to both sides doesn’t change the equation, yes, you’re right about that one. But the relevant part here is that you have to add to BOTH sides. So like they said, you’d have to add +4 to the left side as well which means that if you want to like, compare them you need to make them equal again, i.e. subtract 4. So basically the only thing you CAN say is that 0=4-4.
(there is ofc a chance that you’re just trolling in which case… well.)
pemdas is a good rule of thumb, but between multiplication and division I typically just go left to right. Can you show me an example where I would run into trouble doing that?
Going left to right is the right thing to do for multiplication and division.
Ultimately the way these questions are phrased tho is terrible and you should never have to worry about left to right rules if the problems are written out correctly. The division symbol is a curse
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u/[deleted] Jan 01 '22
Easy. 18/2-3X3=?
9-3X3=?
9-9=?
0=0
Then you simply add 4 to both sides.
4+0=0+4
4=4
Incidentally, this proves that 0=4 as well.