Please answer the 63rd Q.

63 .   If   z   =   4   +   3 i ,   then   z 4   -   16 z 3   +   114 z 2   -   400 z   +   630   is

(1) 0                  (2) 5
(3)  - 5                (4) 625


 

Dear student
Given: z=4+3iz2=4+3i2=16-9+24i=7+24iNow, z3=z×z2=4+3i7+24i=28+96i+21i-72=117i-44and z4=z22=7+24i2=49-576+336iConsider, z4-16z3+114z2-400z+630=49-576+336i-16117i-44+1147+24i-4004+3i+630=49-576+336i-1872i+704+798+2736i-1600-1200i+630=5
Regards

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