Answer: it should be the last one !!!
Step-by-step explanation:





The second equation gives

, but

for any real

, so we can ignore this equation.
This leaves us with

where

is any integer.
Answer:
12.5 feet
Step-by-step explanation:
He only needs 10/12 of a 15 foot long piece of wood. We need to find 10/12 of the length of the wood.
That is:
10/12 * 15 = 12.5 feet
He only needs 12.5 feet of the piece of wood.