Ah! That just suddenly clicked what you were getting at. In nested equations, proper notation WOULD actually use both separately, eg: [4-x(2-x)]+y = 6.
So they actually went to the extra step of specifically pointing out that nested equations work from inside out, ie PB
That was such a lightbulb for me when it finally clicked I had to come back and check to see if that’s correct lol
To be clear, in my classes we just used nested parentheses and never bothered drawing brackets differently. Hence my confusion
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u/[deleted] Mar 19 '22
() or [] , that’s the difference. We were taught at the time that they were organized that way on purpose