Answer:
2x + 9 = 21
Step-by-step explanation:
Looking at option C;
2x + 9 = 21
Step 1: Subtract 9 from both sides
2x+9 - 9 = 21 - 9
2x = 12
Step 2: divide both sides by 2
2x/2 = 12/2
x = 6
Hence the expression which is a two-step equation is 2x + 9 = 21 since we arrived at the solution in two steps
