The unknown number of one equation in the equation group is expressed by an algebraic expression containing another unknown number, which is substituted into another equation, and the linear equation is obtained by eliminating one unknown number, and finally the solution of the equation group is obtained. ?
Steps of Solving Binary Linear Equations with method of substitution;
① Choose a binary linear equation with simple coefficients for deformation, and use an algebraic expression containing one unknown to represent another unknown.
(2) Substitute the deformed equation into another equation, eliminate an unknown number and get a linear equation. (When substituting, it should be noted that it cannot be substituted into the original equation, but can only be substituted into another equation without deformation, so as to achieve the purpose of elimination. )
(3) Solve this one-dimensional linear equation and get the unknown value.
④ Substitute the obtained unknown values into the deformation equation in ①. Find the value of another unknown.
⑤ Simultaneous two unknowns plus "{"is the solution of the equations.
⑥ Final test (substituting into the original equation to test whether the equation satisfies left = right).
Matching method of quadratic equation with one variable
1, the original equation becomes a general form.
2. Divide both sides of the equation by the quadratic term coefficient, so that the quadratic term coefficient is 1, and the constant term is moved to the right of the equation.
3. Add the square of half the coefficient of the first term to both sides of the equation.
4. Match the left side to be completely flat and the right side to be constant.
5. In addition, the solution of the equation is obtained by direct Kaiping method. If the right side is nonnegative, the equation has two real roots. If the right side is negative, then the equation has a pair of imaginary roots of yoke.