The vector z=3-4i is turned anticlockwise through an angle of 180∘ and stretched 2.5 times. The complex number corresponding to the newly obtained vector is
+10i
3-4i i.e., (3,-4) lie in fourth quadrant in complex plane, after turned anticlock through 180∘ this will lie in II quadrant, therefore, the number will be -3+4i, now after streching it 2.5 times i.e., multiplying by 2.5, the required complex number will be −152+10i.