No, I don't think that works. We know that
Letting and yields a root that we already know...
for example, there is a function f(x)= x3+ax2+bx+c=0 with roots Q,W,E
then teachers told me that by substituting y=x2 , then we can find out f(y)=0 s.t. it has roots Q2,W2,E2
but why such substition can help us to find out equations with root Q2,W2,E2? What are the reasons behind?
Thanks for your kind helpings
oh, i mean by sub. y=x2, then x3+ax2+bx+c = 0 becomes
x(x2+b) = -(a2+c)
y(y2+2by+b2) = (a2y2+2acy+c2)
y3+2by2+b2y = a2y2 + 2acy + c2
then eqaution y3+y2(2b-a2)+y(b2-2ac)-c2 =0, has required root, sorry for the misleading of using same function notication