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Class 9 Maths — Linear equations in two variables

Find solutions of an equation like 2x + y = 7 and read its graph as a straight line.

Name: ________________________

  1. 1.The line 2x + y = 6 crosses the y-axis. Give the y-coordinate of that crossing point.

  2. 2.How many solutions does a linear equation in two variables have?

    • a) None
    • b) Infinitely many
    • c) Exactly two
    • d) Exactly one

  3. 3.In the equation 2x + y = 7, what is y when x = 3?

  4. 4.Written in the form ax + by + c = 0, the equation 3x = 5 has a = 3 and c = -5. What is b?

  5. 5.The graph of every linear equation in two variables is...

    • a) a single point
    • b) a straight line
    • c) a circle
    • d) a curve

  6. 6.The x-axis itself is a line. Its equation is y = what?

  7. 7.Two numbers add up to 12. Calling them x and y, the equation is x + y = c. What is c?

  8. 8.Sort each equation by whether it is linear in two variables.

    Groups: Linear in two variables · Not linear in two variables

    • x³ = y
    • x + y = 0
    • y = 5x - 1
    • 2x + 3y = 6
    • xy = 12
    • x² + y = 4

Answer key — Class 9 Maths — Linear equations in two variables

  1. 1. 6
  2. 2. b) Infinitely many
  3. 3. 1
  4. 4. 0
  5. 5. b) a straight line
  6. 6. 0
  7. 7. 12
  8. 8. 2x + 3y = 6 → Linear in two variables; x² + y = 4 → Not linear in two variables; y = 5x - 1 → Linear in two variables; xy = 12 → Not linear in two variables; x + y = 0 → Linear in two variables; x³ = y → Not linear in two variables