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Revision Notes

Pair of Linear Equations in Two Variables

Punjab Board · Class 10 · Mathematics

Quick revision notes for Pair of Linear Equations in Two Variables — Punjab Board Class 10 Mathematics. Key concepts, formulas, and definitions for last-minute revision.

45 questions30 flashcards5 concepts

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A comparison of the three possible graphical representations of a pair of linear equations in two variables: intersecting lines (unique solution), parallel lines (no solution), and coincident lines (i
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Key Topics to Revise

1

General Form and Basic Concepts

  • The general form of a linear equation in two variables is: a₁x + b₁y + c₁ = 0, where a₁, b₁, and c₁ are real numbers and a₁ ≠ 0, b₁ ≠ 0.
  • A pair of linear equations in two variables is also called a system of simultaneous linear equations.
  • The solution of a pair of linear equations is an ordered pair (x, y) that satisfies both equations at the same time.
2

Ratio Conditions and Nature of Solutions

  • By comparing the ratios a₁/a₂, b₁/b₂, and c₁/c₂, we can determine the nature of the solution WITHOUT actually solving the equations.
  • CONDITION 1 — Unique Solution (Intersecting Lines, Consistent): a₁/a₂ ≠ b₁/b₂
  • CONDITION 2 — Infinitely Many Solutions (Coincident Lines, Consistent/Dependent): a₁/a₂ = b₁/b₂ = c₁/c₂
3

Graphical Method of Solving

  • In the graphical method, we draw the graphs of both equations on the same coordinate plane.
  • Find at least TWO solutions (x, y) for EACH equation to draw the line accurately.
  • The point where the two lines intersect gives the solution of the pair of equations.
4

Substitution Method

  • In the substitution method, we express one variable in terms of the other from one equation, and substitute it into the second equation.
  • This converts the system of two equations in two variables into ONE equation in ONE variable, which is easy to solve.
  • After finding one variable's value, substitute it back to find the other variable.

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Full Notes

Key Concepts

An equation of the form axTwo linear equations considered togetherFor equations a₁x + b₁y +Plot both equations as straight linesStep 1

Frequently Asked Questions

What are the important topics in Pair of Linear Equations in Two Variables for Punjab Board Class 10 Mathematics?
Key topics in Pair of Linear Equations in Two Variables include Complete Chapter Overview — Pair of Linear Equations in Two Variables, Pair of Linear Equations - Concept Overview, Process flowchart showing steps to convert a real-world problem into a pair of linear equations. These are the concepts Punjab Board Class 10 examiners draw on most — study them first, then practise related questions.
How to score full marks in Pair of Linear Equations in Two Variables — Punjab Board Class 10 Mathematics?
Understand the core concepts first, then work through the 45 practice questions available for this chapter. Revise formulas and definitions regularly, and use flashcards for quick recall before the exam.

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