Problem: For all real numbers x,x[x{x(2−x)−4}+10}+1=
Answer Choices:
A. −x4+2x3+4x2+10x+1
B. −x4−2x3+4x2+10x+1
C. −x4−2x3−4x2+10x+1
D. −x4−2x3−4x2−10x+1
E. −x4+2x3−4x2+10x+1
Solution:
x[x{x(2−x)−4}+10]+1=x[x{2x−x2−4}+10]+1=x[2x2−x3−4x+10]+1=−x4+2x3−4x2+10x+1