The correct option is
A 1x2+1+22(x2+1)2+5(x2+1)3solving through substitution method
x2+1=k⇒x2=k−1
substituting in the question equation
(k−1)2+24(k−1)+28k3=k2+22k+5k3
=1k+22k2+5k3
=1(x2+1)+22(x2+1)2+5(x2+1)3 [we know that k=x2+1]
x4+24x2+28(x2+1)3=1(x2+1)+22(x2+1)2+5(x2+1)3