What is a trojan horse and whose idea was it

The trojan horse is a story from the Trojan War about the Greeks giving a large wooden horse to the Trojans as a peace offering. The Trojans (Greeks enemy) didn't know that there were Greek soldiers hiding inside the large wooden horse. When the Trojans took the wooden horse inside the city. Greek soldiers sneaked out from the wooden horse and opened the gates to let the Greeks in, to capture the city.

The idea was from Odysseus.

substitute y = 2x - 4 to x + 2y = 12:

x + 2(2x - 4) = 12     use distributive property

x + (2)(2x) + () = 12

x + 4x - 8 = 12     add 8 to both sides

5x = 20     divide both sides by 5

x = 4

put the value of x to the first equation:

y = 2(4) - 4

y = 8 - 4

y = 4