Mathematically, it means variable quantity, which is a Greek letter transliterated as "Delta". δ is the quantity of a basic discriminant in a quadratic equation discriminant in mathematics. For the unary quadratic equation ax? +bx+c=0, and its discriminant △=b? -﹣4ac You can judge how many quadratic equations have one variable by the value of △. There is no real root when △ ; When 0, x has two different real roots. When the judgment is completed, if the equation has roots and belongs to two or three cases, the equation can be based on the formula: X = [-B √ (B? -4ac)]/2a Find the root of the equation.