Is 2+i a solution of z^2-4z+5=0? Please help!!!!!!! :(
z^2 - 4z + 5 = 0
(Note that the square of i is equal to -1)
(2 + i)^2 - 4(2 + i) + 5
= 4 + (i^2) + 4i - 8 - 4i + 5
= 4 - 1 - 8 + 5
= 9 - 9
= 0
Hence, yes, it is a solution.
(Note that the square of i is equal to -1)
(2 + i)^2 - 4(2 + i) + 5
= 4 + (i^2) + 4i - 8 - 4i + 5
= 4 - 1 - 8 + 5
= 9 - 9
= 0
Hence, yes, it is a solution.