a) [tex] (x-1)^{2} = -25 \\ x^{2} -2x+1+25=0 \\ delta=4-4*26=4-104=-100 \\ x_{1} = \frac{2-10i}{2} = 1-5i
x_{2} = \frac{2+10i}{2} = 1+5i[/tex]
b([tex] x^{2} -8x+32=0 \\ delta=64-4*32=64-128=-64 \\ x_{1} = \frac{8-8i}{8} =1-i \\ x_{2} = \frac{8+8i}{8} =1+i[/tex]
c) [tex] x_{1} =4i \\ x_{2} =-4i[/tex]