Multiple Response. Select all the equations that have exactly one solution.

A. 3x + 1 = -3x + 7
B. 3x + 1 = x + 1
C. 3x + 1 = 3x + 7
D. 3x + 1 = 1/2 (1x + 1)
E. 3x + 3 = 3(x+1)