(1-3i)10 = [(1-3i)2]5 = [ 1 - 9 -6i]5 = [ -8 -6i]5 = (-2)5 [ 4 +3i]5
= (-2)5 [ 4 +3i]2[ 4 +3i]2[ 4 +3i] = (-2)5 [ 16-9 + 24i ][ 16-9 + 24i ][ 4 +3i]
= -32[ 7 + 24i ][ 7 + 24i ][ 4 +3i] = -32[ 49 - 576 + 336i ][ 4 +3i]
= -32[ - 527 + 336i ][ 4 +3i] = -32[ - 2108 - 1008 - 1581i + 1344i ] = 32 [ 3116 + 237i ]
Modulus of (1-3i)10 = 32 { sqrt ( 3116* 3116 + 237*237 ) } = 32 { 3125 } = 100000