Please answer this quick with an explanation: On which line does an error first occur in process of finding the inverse of g(x)?

Line 1: g(x) = (x+2)^3/4 -1

Line 2: y= (x+2)^3/4 -1

Line 3: y+1 = (x+2)^3/4

Line 4: (y+1)/4= (x+2)^3

Line 5: square root to the power of 3 of (y+1)/4 = x+2

Line 6: square root to the power of 3 of (y+1)/4 -2= x

Line 7: g^-1 (x) = square root to the power of 3 of (x+1)/ 4 -2