Why are equations like w - x + x = w called identities?

Suppose that one doll house uses the 1 inch scale, meaning that 1 inch on the doll house corresponds to 1/2 foot for life-sized objects. if the doll house is 108 inches wide, what is the width of the full-sized house that it's modeled after? in inches and feet.

In the geometric progression –3, 12, −48… what term is 3,072?

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