A, 2^12.
3x - y = 12 can also be written as 3x - 12 = y
The fraction is 8^x / 2^y,
Substitute y = 3x - 12 into fraction,
8^x / 2^[3x - 12]
= 8^x / [(2^3)^x × 2^(-12)]
= 8^x / [(2 × 2 × 2)^x × 2^(-12)]
= 8^x / [8^x × 2^(-12)]
{8^x can be factorised out of numerator and denominator of fraction}
= 1 / 2^(-12)
{When the denominator becomes numerator, the power sign is switched from - to +}
= 2^(12)
Hope this helps! :)
