y cut a piece of wood into 3 pieces of the same length. after he cuts off 2 feet from one of the pieces, he is left with piece that is 5 feet long. what is the length of the piece of wood he started with?

Answer 1

x-2 = 5
x = 7

3x = 21

Answer 2

X-2=5
×=5+2 (change sign because you transpose -2 to the other side so that it will become +)
X=7

3 (x)=?
3 (7) (the unknown or the is 7 👆 so that you have to subtitute it)
3 (7)=21 ( the length of the piece of wood he started with 21 )