Squaring the Binomial

[Albert Chan]

Instead of purging variables, we can quote them. (quote(expr) == 'expr')
Quoting returns its argument unevaluated.

Cas> a:=b:=c:=1
Cas> expand('(12*c^4 + 1/4*a^6*c)^2')

1/16*a^12*c^2+6*a^6*c^5+144*c^8

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BUG report: sometimes quoting does not work.
HP Prime emulator 2.1.14181 (2018 10 16):

Cas> expand('(12*c^4 + 1/4*a^6*c)^2')

150.0625

Not only quote not working, results somehow turned approximate.