Have you ever seen a pot of water on the stove? What have you observed about the water as heat is added to it? How do you think the addition of heat to the water is related to a change of state?

Explanation:

Ok so the change of the state is gas because u are boiling water so the water get hotter and then gas starts to come out of the water because of how hot it is

try using substitution:

x + y - 6 = x - y. (i'm not giving you the exact answer). since 0 = x - y, then sub 0 in the equation with x - y. combine your like terms, and then use inverse operations, and you'll have your answer.

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