Linear equation in two variables - ESSENTIAL POINTS


  • Linear equation in two variables is an equation of the form ax + by + c = 0, where a, b and c are real numbers, such that a and b are not both not equal to zero.
  • The solution of a linear equation is not affected when
    • the same number is added to (subtracted from) both sides of the equation,
    • both sides of the equation are multiplied or divided by the same non-zero number.
  • A linear equation in two variables has infinitely many solutions.
  • The graph of every linear equation in two variables is a straight line.
  • The equation of the y-axis is x = 0 and the equation of the x-axis is y = 0.
  • The graph of x = a is a straight line parallel to the y-axis and the graph of y = a is a straight line parallel to the x-axis.
  • An equation of the type y = mx represents a line passing through the origin.
  • Every point on the graph of a linear equation in two variables is a solution of the linear equation. Moreover, every solution of the linear equation is a point on the graph of the linear equation

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