Question

How to solve x - 21 = 9

Answer 1

you add 21 on both sides.the -21 and 21 cancel out, leaving x by it self while 9 gets added with 21 which equals 28, making x=28

Answer 2

x=28

Explanation:

add 21 to both sides and you get

x-21+21=9+21

then you get x+0=30

x=30