Problem: The roots of the equation 2x+2x−21=5 can be found by solving:
Answer Choices:
A. 16x2−92x+1=0
B. 4x2−25x+4=0
C. 4x2−17x+4=0
D. 2x2−21x+2=0
E. 4x2−25x−4=0
Solution:
2x+x2=5. Squaring, we obtain 4x+8+x4=25. Multiply both sides of the equation by x and obtain 4x2−17x+4=0.