1, substitution elimination method

Substitution elimination method is a method to solve equations by substituting unknowns. The basic step of this method is to select an unknown, replace it with another unknown or constant, and then solve a new unknown. This method is very common in solving binary linear equations.

2. Addition, subtraction and elimination method

Addition, subtraction and elimination method is a method to solve equations by adding or subtracting the same terms. The basic step of this method is to select an unknown, add or subtract another unknown or constant to make the coefficients of this unknown equal, and then solve this unknown. This method is also common in solving binary linear equations.

3. Formula method

Formula method is a method to solve equations by using mathematical formulas. The basic step of this method is to find the relationship between the roots and coefficients of the equation, and then use this relationship to solve the unknown quantity. This method is suitable for all kinds of equations, including univariate quadratic equation and univariate higher order equation.

Matters needing attention in solving equations:

1. Carefully examine the questions: Before solving the equation, you must carefully examine the questions and understand the conditions and requirements in the questions. If there are many unknowns or complex equations in the topic, you need to patiently solve them one by one. At the same time, we need to pay attention to details such as units and symbols.

2. Choose the right method: There are many ways to solve the equation, so it is necessary to choose the right method according to the specific situation. For example, simple linear equations can be solved directly by substitution or addition and subtraction; For complex nonlinear equations or equations with many unknowns, we need to use more advanced methods such as iterative method, elimination method or matrix method.

3. Check the answer: After getting the solution of the equation, you need to check whether the answer is reasonable and meets the meaning of the question. You can verify the answer by substituting it into the original equation, or you can judge whether the answer is correct according to the actual meaning of the question.

4. Pay attention to the calculation accuracy: when solving the equation, you need to pay attention to the calculation accuracy. If you use a computer or calculator to calculate, you need to pay attention to rounding error and floating-point precision. If you need high-precision calculation results, you can use some special high-precision calculation libraries or tools.