The work of a student to find the dimensions of a rectangle of area 8 + 16x and width 4 is shown below:

step 1: 8 + 16x
step 2: 4(4) + 4(12x)
step 3: 4(4 + 12x)
step 4: dimensions of the rectangle are 4 and 4 + 12x

in which step did the student first make an error and what is the correct step?

step 3; 4 + (4 + 12x)
step 3; 4 + (4 ⋅ 12x)
step 2; 4(2) + 4(4x)
step 2; 4(2) + 4x(2)

best answer gets !