Given f(x) = 2x – 3, for what value of x does 2*[f(x)] – 21 = f(x – 4) ?  Answers.
A) 0
B) 2
C) 4
D) 6
E) 8

Rationale: "2 ( 2 x - 3 ) - 21 = 2 ( x - 4 ) - 3 2 x = 16 x = 8 the answer is e ."
Answer: E