# Reasoning with Equations and Inequalities (A-REI)

## Quadratic Formula

CC.9-12.A.REI.4b – Solve quadratic equations by inspection (e.g., for x2 = 49), 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.

## Solving Inequalities

CC.9-12.A.REI.3 – Solve linear equations and inequalities in one variable, including equations with coefficients represented by letters.

## Solving Equations

CC.9-12.A.REI.1 – Explain each step in solving a simple equation as following from the equality of numbers asserted at the previous step, starting from the assumption that the original equation has a solution. Construct a viable argument to justify a solution method.

## Solve Linear Formulas and Literal Equations For a Specified Variable

CC.9-12.A.CED.1 & CC.9-12.A.REI.3 – Create equations and inequalities in one variable and use them to solve problems.