what are the roots of the equation x2 + 58 = 4?

If the x2 is x^2 then :
x^2 + 58 = 4
move four over
x^2 +58 -4 =0
x^2 + 54+   = 0
(x^2 +729 )^2= -729
x^2 = -1458
x= + or - the square root of -1458
+ or -  2i ( square root of 13)

Num of plants = (original#ofplants)*(1.6)^t

How am i goonna know explain