The steps below show the incomplete solution to find the value of x for the equation
6x − 2x − 5 = −6 + 21:
step 1: 6x − 2x − 5 = −6 + 21
step 2: 6x − 2x − 5 = 15
step 3: 4x − 5 = 15
which of these is most likely the next step?
4x=10
4x=3
4x=45
4x=20