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Detailed derivation process of root formula of quadratic equation in one variable
The detailed derivation process of the root formula of quadratic equation in one variable;

The root formula of unary quadratic equation is derived by collocation method, so the detailed process of deriving the root formula from AX 2+BX+C (the basic form of unary quadratic equation) is as follows.

1, ax 2+bx+c = 0 (a ≠ 0, 2 stands for square), and two sides of the equation are divided by a to get x 2+bx/a+c/a = 0.

2. The shifted term is x 2+bx/a =-c/a, and both sides of the equation are added with the square of half the coefficient of the first term b/a, that is, both sides of the equation are added with b 2/4a 2.

3. The formula X 2+BX/A+B 2/4A 2 = B 2/4A 2-C/A, that is, (X+B/2A) 2 = (B 2-4AC)/4A.

4. X+B/2A = [√ (b 2-4ac)]/2A (√ stands for the number of roots) can be obtained after finding the roots, and finally X = [-b √ (b 2-4ac)]/2A can be obtained.

The Root Formula of the First and Second Equation

1、

2. Description of the formula: the form of the unary quadratic equation: ax2+bx+c=0(a≠0, A, B and C are constants).

3. Meet the conditions:

(1) is an integral equation, that is, both sides of the equal sign are algebraic expressions, if there is a denominator in the equation; And the unknown is on the denominator, then this equation is a fractional equation, not a quadratic equation. If there is a root sign in the equation and the unknown is within the root sign, then the equation is not a quadratic equation (it is an irrational number equation).

(2) contains only one unknown number.

(3) The maximum number of unknowns is 2.