t²-[(√2+2)+(√2-2)]t+(2-4)=0
t²-(√2+2)t-(√2-2)t+(√2+2)(√2-2)=0
t[t-(√2+2)]-(√2-2)[t-(√2+2)]=0
[t-(√2+2)][t-(√2-2)]=0
t=√2+2,t=√2-2
t²-[(√2+2)+(√2-2)]t+(2-4)=0
t²-(√2+2)t-(√2-2)t+(√2+2)(√2-2)=0
t[t-(√2+2)]-(√2-2)[t-(√2+2)]=0
[t-(√2+2)][t-(√2-2)]=0
t=√2+2,t=√2-2