решите уравнение . 2x^4-52x^2+50=0

2x^4-52x^2+50=0   /2
x^4-26x^2+25=0
x^2=t
t^2-26t+25=0
D=b^2-4ac= 26^2-4*25*1=676-100=576
X1=(26-24)/2=1
X2=(26+24)/2=25
t=1                   t=25
x^2=1               x^2=25
x= +1 и -1        x= +5 и -5