Which of the following is an equivalent expression to 7 · (1 + 0.20)3x?
7 · (1.728)x
7 · (3.6)x
343 · (1.2)x
21 · (1.2)x
7 · (1.728)x
7 · (3.6)x
343 · (1.2)x
21 · (1.2)x