Hello,
The rational roots may be all divisors of 100
+1,-1,+2,-2,+4,-4,+5,-5,+10,-10,+20,-20,+25,-25,+50,-50,+100,-100
f(x)=x^4-29x^2+100
f(5)=5^4-29*5^2+100=0 : 5 is a root
f(-5)=(-5)^4-29*(-5)²+100=0 : -5 is a root
f(2)=2^4-29*2²+100=0 : 2 is a root
f(-2)=(-2^)^4-26*(-2)²+100= 0 : -2 is the last root.
