Specific practices

according to

Matters needing attention

Denominator:

Both sides of the equation are multiplied by the least common multiple of the denominator at the same time (basic property 2 of the equation)

Not wearing a seat belt:

1. Parentheses are preceded by a "+". Remove the brackets and the "+"in front of them, and the symbols of the items in brackets remain unchanged.

There is a "-"before the brackets. Remove the brackets and the preceding "-"sign, and the symbol of each item in brackets should be changed to the opposite symbol.

The basis of the law of bracket removal is actually the law of multiplication and distribution.

Pay attention to the symbol before brackets, which is the basis for whether the items in brackets change their symbols after removing brackets.

When deleting brackets, the symbol before brackets should be deleted together with brackets.

It should be noted that when there is a "-"sign in front of the brackets, the symbols of the items in brackets will change 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.

If there is a numerical factor in front of the brackets, before removing the brackets, multiply the number with the items in brackets by multiplication and division to avoid mistakes.

When you encounter multiple layers of brackets, you usually remove the brackets from inside to outside, and you can also count the number of "-"from outside to inside.

Move items: move items with unknown numbers to the right of the equal sign (usually) and to the left of other equal signs. Pay attention to changing signs when moving items.

merge

: Merge similar projects.

Add up the coefficients and keep the others the same.

Coefficient 1: the basic properties of coefficient equation with two sides divided by unknown number 2