The root formula of quadratic equation in one variable is derived by collocation method. The detailed process of deriving the root formula from AX 2+BX+C (the basic form of quadratic equation in one variable) 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. If the term is shifted, x 2+bx/a =-c/a, the square of half the coefficient b/a of the first term is added to both sides of the equation, that is, b 2/4a 2 is added to both sides of the equation.

3. The formula of x 2+bx/a+b 2/4a2 = b 2/4a2-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.

One, one yuan quadratic Hu Wang root formula

1, formula description: unary quadratic equation form: ax2+bx+c=0(a≠0, and a, b and c are constants).

2. 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.