12-[20-2(6^2/3•2^2)]
12-[20-2(6²/32²)]=12-[20-2(36/34)]=12-[20-2(12*4)]=12-[20-2(48)]=12-[20-96]=12-(-76)=12+76=88
\(12-\bigg{[}20-2\cdot \bigg{(} \frac{\big{6^2}}{\big{3}} \cdot2^2\bigg{)}\bigg{]}=12-\bigg{[}20-2\cdot \bigg{(} \frac{\big{36}}{\big{3}} \cdot4\bigg{)}\bigg{]}=\\\\=12-(20-2\cdot 12 \cdot4)=12-(20-96)=12-(-76)=12+76=88\)
