There are many such topics, meaning "simplify first, then evaluate"

Simplification means "merging similar projects". After merging, the value of the formula is calculated according to the given value of the unknown quantity.

For example: -a 2+b-a 2-b =-2a 2

If the title says that the value of a is 2, it is:

Solution: When a=2,

Original formula =-2 * 2 2

? =-2*4

=-8?

A: The value is -8.

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