Stage 11 · Quadratic Equations
11.5.4 Building an Equation from Its Roots
11.5 The Relationship Between Roots and Coefficients (Vieta's Formulas)
Point 4 of 4
11.5.4 Building an Equation from Its Roots
Core ideaGiven two roots, use Vieta's in reverse: take the sum and product as coefficients to write x²−(sum)x+(product)=0.
Module goal. Read off the sum and product of the two roots without solving, then work backwards to build an equation from its roots and evaluate symmetric expressions.