If there are variables in addition to numbers inside of two pairs of parentheses, you can’t find their exact values. There’s a rule to expand these kinds of parentheses, based on the distributive property.
Rule
Example 1
Expand
Since you don’t know the values of
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Sometimes, there’s a minus sign in front of the parentheses. In those cases, it’s important to move the minus sign to each of the terms inside the parentheses before expanding. If a term inside the parentheses is negative already, it turns positive, because
Rule
Example 2
Expand the expression
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The first term in the expression is expanded like this:
The second term has a minus sign in front of the parentheses, and can be expanded by applying the rule above:
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Then you have that