What is a bracket-removing jingle? To remove brackets or add brackets, the key depends on the hyphen.
There is a plus sign in front of the brackets, and the brackets remain unchanged.
Parentheses are preceded by a minus sign, and when you add parentheses, they change sign.
Both brackets have the problem of "sign change" and "sign change". It's difficult to master "sign change" and "sign constant" correctly, especially when parenthesis is used. If there is a "+"in front of the bracket, there will be a saying of "invariance", that is, if the bracket is removed, the "invariance" in the bracket will be "liberated" from the bracket.
Mathematical bracket removal rule bracket removal: that is, brackets are removed from the formula according to a certain algorithm and order.
The basis of the law of bracket removal in mathematics is actually the law of multiplication and distribution. Note: 1. There is a "+"before the brackets. After removing the brackets and the "+"sign in front of them, the symbol of the original brackets remains unchanged.
There is a "-"before the brackets. After removing the brackets and the preceding "-"sign, the symbol of the original brackets will change. (Replace with the opposite symbol, for example: -(x-y)=-x+y).
Alphabetic formula:1.a+b+c = a+(b+c); 2.a-b-c=a-(b+c).
Precautions for removing the bracket 1. Pay attention to the symbol before brackets, which is the basis for whether the items in brackets change their symbols when brackets are removed.
2. When deleting brackets, delete the symbol before brackets together with brackets.
3. It should be noted that when the minus sign is in front of the brackets, the symbols of the items in the brackets should be changed after the brackets are removed. You can't just change the symbol of the first item or the first few items in brackets and forget to change other symbols.
4. If the number factor is in front of the bracket, before removing the bracket, multiply the number with the items in the bracket by multiplication and division to avoid mistakes.
5. When you encounter a multi-layer bracket, you usually remove the bracket step by step from the inside out, or from the outside in.
6. The basis of the law of multiplication, division and division of brackets is actually one of the laws of multiplication, division and distribution.