[header] How to solve quadratic equations with the " transforming method " [title] Recall the rule of signs. [substeps] If a and c have different signs, roots have different signs if a and c have same sign, roots have same sign. If a and b have different signs, both roots are positive. 
If a and b have same sign, both roots are negative. [title] Transform the equation in standard form ax^2 + bx + c = 0 (1) into a new equation, with a = 1, and the constant c = a * c.