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Mathematics · unit version 1

Algebra reasoning, constraints and solution evidence

A focused school-entry sequence in expression structure, algebraic operations, parameter cases, contextual equations, graph-based solutions and verified matrix methods. Written reasoning and graph construction require review; public practice is not automatic mastery.

Open any lesson. Completion records participation; automatic practice checks and human judgment of written arguments are separate. This unit retains its own versioned requirements.

Readiness and preparation

Check your starting point

Try these short questions on paper, then compare your reasoning. They are optional self-checks, not a placement score or a navigation requirement. Use a targeted review when useful and return with your browser’s Back control.

When may you cancel a common factor?

Rational arithmetic preserves the original domain even after cancellation.

Compare reasoning and find a refresher

The factor must multiply the whole numerator and denominator and be nonzero at the input. A shorter formula does not restore inputs excluded by the original expression.

Review rational restrictions

Why does dividing an inequality by a negative number reverse its direction?

A parameter can change sign or become zero.

Compare reasoning and find a refresher

If u<v then v−u>0. Multiplying by a negative number makes this difference negative, reversing the order. Division by zero is never allowed.

Review inequalities

What does a point on an equation graph represent?

Systems and feasible regions must satisfy every original condition.

Compare reasoning and find a refresher

The coordinates form a pair that makes the equation true. A common point must satisfy both equations; a relation can have several vertical values at the same horizontal input.

Review relations and graphs

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Algebra reasoning: mixed independent evidence

The mixed assessment has separate response history and review criteria; it does not change lesson participation records.

Lesson sequence

Each linked lesson opens on its own page. Expand its details here when you want to check the objectives before choosing.

  1. Read a compound expression as a model

    Lesson details and objectives

    Separate meaningful parts before expanding or calculating.

    • Identify terms, factors and compound subexpressions with contextual units.
    • Predict how changing one input affects a compound expression while other inputs stay fixed.
    • Compare equivalent forms and reject transformations that change the model.

    6 practice tasks.

  2. Operate on polynomials and prove identities

    Lesson details and objectives

    Use coefficient arithmetic and identities with numerical consequences.

    • Add, subtract and multiply polynomials with explicit coefficient tracking.
    • Explain closure using finite sums of nonnegative integer powers.
    • Prove a polynomial identity and use it to generate a numerical relationship.

    6 practice tasks.

  3. Keep domains through rational arithmetic

    Lesson details and objectives

    Add, subtract, multiply and divide expressions without restoring excluded inputs.

    • Compute all four rational-expression operations using polynomial factors.
    • Retain original denominator and divisor restrictions after cancellation.
    • Explain closure algebraically while distinguishing rational functions from their original expression domains.

    6 practice tasks.

  4. Solve inequalities with an unknown coefficient

    Lesson details and objectives

    Separate sign cases before dividing by a parameter.

    • Classify a linear inequality by positive, negative and zero coefficient cases.
    • Explain order reversal using multiplication and test values.
    • Compare a parameter-dependent solution set with contextual restrictions.

    6 practice tasks.

  5. Choose a quadratic method and derive the formula

    Lesson details and objectives

    Turn a square into a solution argument rather than a memorized rule.

    • Derive the quadratic formula by reversible square completion with a nonzero leading coefficient.
    • Select inspection, factoring, square roots or completing the square for a fresh equation.
    • Handle real, repeated and complex solutions without losing square-root branches.

    6 practice tasks.

  6. Construct rational models from rates

    Lesson details and objectives

    Define rates, combine their effects and reject impossible algebraic candidates.

    • Create a rational equation from a work or travel context with consistent units.
    • Solve the equation while retaining physical and algebraic domain conditions.
    • Interpret extraneous, negative or otherwise nonviable candidates against the original model.

    6 practice tasks.

  7. An equation describes a set of points

    Lesson details and objectives

    Test both directions of the connection between an equation and its graph.

    • Test point membership by substituting both coordinates into an implicit equation.
    • Explain why a circle is a graph of an equation even though it is not a single-valued function of x.
    • Preserve domain restrictions and justify that a proposed graph contains exactly the solutions.

    6 practice tasks.

  8. Build a feasible region from constraints

    Lesson details and objectives

    Combine boundary rules, inequalities and contextual integer choices.

    • Construct a half-plane using a boundary and a justified test point.
    • Find the common feasible region and distinguish excluded boundaries, empty sets and unbounded sets.
    • Check whole-number decisions against every contextual constraint.

    6 practice tasks.

  9. Read intersections as simultaneous solutions

    Lesson details and objectives

    Use supplied graphs to find candidates and equations to verify them.

    • Read approximate solutions from a shared-scale pair of graphs.
    • Verify both coordinates in both equations and distinguish a point from an x-coordinate.
    • Recognize zero, one, two and infinitely many solutions, including nonfunctional curves.

    6 practice tasks.

  10. Approximate intersections without inventing solutions

    Lesson details and objectives

    Combine graph candidates, domains and controlled interval refinement across function families.

    • Form f(x)−g(x) and use continuous sign changes to bracket an intersection.
    • Check excluded inputs, asymptotes and extraneous roots before accepting a numerical answer.
    • Compare polynomial, rational, radical, absolute-value, exponential and logarithmic equations.

    6 practice tasks.

  11. Encode and verify a matrix solution

    Lesson details and objectives

    Keep variable order, inverse existence and original equations visible.

    • Encode a three-variable system as Ax=b without changing the variable order.
    • Use and verify a 3×3 inverse when it exists, then check the proposed solution in the original equations.
    • Distinguish singular consistent and inconsistent systems instead of treating failure to invert as no solution.

    6 practice tasks.