Test Yourself
Algebra
Level
4
If 3x−y=12, what is the value of ?
64
256
The value cannot be determined from the information given.
4096
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1 solution
One approach is to express
2 y 8 x
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 2 y 8 x gives
(23)x 2y
which can be rewritten
23x 2y
Since the numerator and denominator have a common base, this expression can be rewritten as 2(3x−y). In the question, it states that 3x−y=12, so one can substitute 12 for the exponent, 3x−y, which means that
8x 2y =212