Nisha did the work below to solve an equation.

step 1 7 b + 3.2 b minus 5 = 18.92
step 2 10.2 b minus 5 = 18.92
step 3 5.2 b = 18.92
step 4 b = 3.64

in which step did nisha make her first error?
step 1
step 2
step 3
step 4