Question

Which expression is equivalent to 21x+9-3x

Answer 1

You can simplify this expression by combining like terms. You can see that you can subtract 3x from 21x leaving us with (your answer): 18x + 9. You could also factor this to look like 9(2x + 1). Whichever one you prefer :))

Answer 2

18x+9 is the correct answer