A1.AREI.4b

Solve quadratic equations by inspection, taking square roots, completing the square, the quadratic formula and factoring, as appropriate to the initial form of the equation. Recognize when the quadratic formula gives complex solutions and write them as a+bi for real numbers a and b. (Limit to non-complex roots.)

Khan Academy Resources

Understanding the quadratic formulaSolving quadratics by completing the squareSolving quadratics by factoring reviewQuadratic formula proof reviewCompleting the square reviewSolving simple quadratics reviewDiscriminant reviewSolving quadratics by taking square roots Quadratic formula reviewSolving quadratics by factoringQuadratic formulaQuadratics by factoring (intro)Completing the square (intermediate)Completing the squareQuadratics by factoringSolve equations by completing the squareSolve equations using structureCompleting the square (intro)Quadratics by taking square roots (intro)Solve quadratic equations: complex solutionsQuadratics by taking square roots: with stepsZero product propertyStrategy in solving quadraticsQuadratic word problem: ballWorked example: completing the square (leading coefficient ≠ 1)Worked example: quadratic formula (negative coefficients)Solving quadratics by taking square rootsSolving quadratic equations: complex rootsCompleting the squareSolving quadratics by factoringSolving quadratics by completing the square: no solutionWorked example: quadratic formula (example 2)Solve by completing the square: Non-integer solutionsSolve by completing the square: Integer solutionsZero product propertyStrategy in solving quadratic equationsSolving quadratics by taking square roots examplesSolving quadratics by taking square roots: with stepsSolving quadratics by factoring: leading coefficient ≠ 1Worked example: Rewriting & solving equations by completing the squareQuadratics by taking square roots: strategyWorked example: Rewriting expressions by completing the square

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