We have,
If 2x−12x=13
Then, squaring both side and we get,
(2x−12x)2=(13)2
4x2+14x2−2×2x×12x=169
4x2+14x2=169+2
4x2+14x2=171
4x2+14x2=171
Again, squaring both side and we get,
(4x2+14x2)2=(171)2
16x4+116x4+2×4x2×14x2=29241
16x4+116x4=29241−2
16x4+116x4=29239
Hence, this is the answer.