Equations — O/L Mathematics

What must I remember about Equations?

• Linear equations with one unknown are solved by isolating the variable using balanced inverse operations on both sides.
• Simultaneous linear equations with two unknowns (ax + by = c and dx + ey = f) are solved via elimination or substitution.
• Elimination method: Equalise the absolute coefficients of one variable by scaling equations, then add or subtract to eliminate that variable.
• Substitution method: Express one variable in terms of the other from one equation and substitute into the second equation.
• Word problem formulation: Clearly define algebraic variables representing unknowns with units, construct mathematical equations, solve, and interpret in context.

Test yourself (1 minute)

1. Sign-checking in elimination

   If matching coefficients have IDENTICAL signs, SUBTRACT the equations; if they have OPPOSITE signs, ADD the equations.

2. Verification step

   Always substitute your calculated values of x and y back into BOTH original equations to confirm they satisfy both.

3. Do not stop at finding x

   A frequent error in Paper 1 Part B is finding x and forgetting to substitute back to calculate y and state contextual quantities.

Practise Equations questions today

Source: NIE G.C.E. (O/L) Mathematics Syllabus (Grade 10, Unit 14)

What should I study first?

What comes next?

Next in the syllabus

Where does Equations fit in the syllabus?

Grade 10 · Term 2 · Grade 11 · Term 2