Algebra and equations

Simplify expressions, interpret sequences and rearrange formulae, then solve linear, simultaneous and quadratic equations with domain checks.

  • 13 lessons

Notation, evaluation and algebraic models

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SEAB syllabus · 2027 · MOE syllabus

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About this topic

Before you begin

Simplify expressions, interpret sequences and rearrange formulae, then solve linear, simultaneous and quadratic equations with domain checks.

Learning goals
  • Evaluate an algebraic expression by substitution
  • Represent a situation with algebraic expressions
  • Interpret algebraic notation and represented operations
  • Express and use the general term of a sequence
  • Simplify linear expressions by combining like terms
  • Formulate, use and interpret a mathematical model
  • Solve linear equations and check the solution
  • Expand and factorise algebraic expressions
  • Change the subject of a formula
  • Multiply and divide algebraic fractions with domain restrictions
  • Solve a first-degree equation by a specified expansion or denominator-clearing step, preserving original exclusions
  • Solve a system of linear equations completely, including systems with no or infinitely many solutions
  • Solve simultaneous equations by justified methods
  • Interpret and draw graphs of functions
  • Apply the quadratic formula with signed coefficients, both branches and the complete real solution set
  • Solve quadratic equations by suitable methods
Syllabus statements covered
  • Using letters to represent numbers
  • Interpreting notations: ab as a × b; a/b as a ÷ b or a × (1/b); a² as a × a, a³ as a × a × a, a²b as a × a × b, …; 3y as y + y + y or 3 × y; 3(x + y) as 3 × (x + y); (3 ± y)/5 as (3 ± y) ÷ 5 or (1/5) × (3 ± y)
  • Evaluation of algebraic expressions and formulae
  • Translation of simple real-world situations into algebraic expressions
  • Recognising and representing number sequences, including nth term for simple cases such as n + 3, 2n + 1
  • Addition and subtraction of linear expressions
  • Simplification of linear expressions such as −2(3x − 5) + 4x and 2x/3 − 3(x − 5)/2
  • Expansion of the product of two linear expressions
  • Multiplication and division of simple algebraic fractions such as (3a/(4b²))(5ab/3); (3a/4) ÷ (9a²/10)
  • Changing the subject of a simple formula
  • Finding the value of an unknown quantity in a given formula
  • Factorisation of linear expressions ax + kay
  • Factorisation of quadratic expressions x² + px + q. Exclude (a ± b)² = a² ± 2ab + b² and a² − b² = (a + b)(a − b), and addition/subtraction of algebraic fractions such as 1/x + 1/(x − 1).
  • Solving linear equations in one variable
  • Solving simple fractional equations that reduce to linear equations, such as x/3 + (x − 2)/4 = 3 and 3/(x − 2) = 6
  • Graphs of linear equations in two variables ax + by = c
  • Solving simultaneous linear equations in two variables by substitution and elimination or graphically
  • Solving quadratic equations in one variable by formula
  • Formulating a linear or quadratic equation in one variable or a pair of linear equations in two variables to solve problems
  • Using letters to represent numbers
  • Interpreting notations: ab as a × b; a/b as a ÷ b or a × (1/b); a² as a × a, a³ as a × a × a, a²b as a × a × b, …; 3y as y + y + y or 3 × y; 3(x + y) as 3 × (x + y); (3 + y)/5 as (3 + y) ÷ 5 or (1/5) × (3 + y)
  • Evaluation of algebraic expressions and formulae
  • Recognising number sequences (including evaluating simple nth term like n + 3 and 2n + 1)
  • Translation of simple real-world situations into algebraic expressions
  • Addition and subtraction of linear expressions
  • Simplification of linear expressions such as −2(3x − 5) + 4x; 2x/3 − 3(x − 5)/2
  • Solving linear equations in one variable
  • Formulating a linear equation in one variable to solve problems
  • Recognising and representing number sequences (include finding an algebraic expression for the nth term for simple cases such as n + 3 and 2n + 1)
  • Expansion of the product of two linear expressions
  • Multiplication and division of simple algebraic fractions such as (3a/(4b²))(5ab/3); (3a/4) ÷ (9a²/10)
  • Changing the subject of a simple formula
  • Finding the value of an unknown quantity in a given formula
  • Factorisation of linear expressions of the form ax + kay
  • Factorisation of quadratic expressions of the form x² + px + q. Exclude: use of (a ± b)² = a² ± 2ab + b² and a² − b² = (a + b)(a − b); addition and subtraction of algebraic fractions such as 1/x + 1/(x − 1)
  • Graphs of linear equations in two variables (ax + by = c )
  • Solving simple fractional equations that can be reduced to linear equations such as x/3 + (x − 2)/4 = 3; 3/(x − 2) = 6
  • Solving simultaneous linear equations in two variables by * substitution and elimination methods * graphical method
  • Formulating a pair of linear equations in two variables to solve problems
  • Solving quadratic equations in one variable by use of formula
  • Formulating a quadratic equation in one variable to solve problems

Choose a lesson

Work through them in order.

  1. Not startedNotation, evaluation and algebraic modelsNextInterpret grouped algebraic notation and define a letter before substituting a value.
  2. Not startedRead a sequence ruleUse the given position in a stated rule without confusing the term value with its index.
  3. Not startedLinear expressions with integer coefficientsDistribute every sign through a bracket and combine only like terms.
  4. Not startedLinear expressions with fractional coefficientsUse common denominators to combine fractional linear coefficients without losing bracket signs.
  5. Not startedLinear equations with integer coefficientsApply the same reversible operation on both sides and check the answer in the original equation.
  6. Not startedEquations as balanced relationshipsPreserve equality through each solution step and test a candidate solution in the original equation.
  7. Not startedSequences and nth termsRelate a position to its term and distinguish a matching rule from evidence of a unique pattern.
  8. Not startedCommon factors and formula subjectsReverse distribution, change a formula's subject and find an unknown value from the given quantities.
  9. Not startedProducts and simple quadratic factorsDistribute two linear factors and reverse the product for monic quadratics.
  10. Not startedAlgebraic fraction products and domainsCancel factors rather than terms and preserve exclusions when multiplying or dividing algebraic fractions.
  11. Not startedFractional linear equationsClear every denominator and check both the original domain and the solution.
  12. Not startedSimultaneous linear equationsConstruct two linear graphs, solve for their common pair and check graphical readings with algebra.
  13. Not startedQuadratic formula and modelsIdentify coefficients, retain both possible roots and reject values only for a stated domain reason.