One approach is to express
so that the numerator and denominator are expressed with the same base.
Since 2 and 8 are both powers of 2, substituting
23 for 8 in the numerator of
gives
which can be written as
,
since the numerator and denominator of
have a common base, this expression can be rewritten as
23x−y.
It is given that
3x−y=12,so one can substitute 12 for the exponent,
3x−y,giving that expression
is equal to
212 Choices B and C are incorrect because they are not equal to
212.Choice D is incorrect because the value of
can be determined.