Problem: If x−1​−x+1​+1=0, then 4x equals:
Answer Choices:
A. 5
B. 4−1​
C. 0
D. 141​
E. no real value
Solution:
x−1​+1=x+1​;∴x−1+2x−1​+1=x+1. ∴2x−1​=1;∴4x−4=1; and ∴4x=5. (This value of x satisfies the original equation.)