One-Variable Equations Practice: Keep Both Sides Balanced

An equation states that two expressions have the same value. Solving it means preserving that equality while isolating the unknown. Think of doing the same operation to both sides instead of memorising that a term ‘jumps across’ and changes sign.

Original foundation practice · choose by prerequisite skill.

PREDICT · CHANGE · EXPLAIN

Compare an expression with a target

The expression y=3x+2 equals 17 only at one x-value. Predict x, move the slider, then verify it by substitution.

010320x (units)3x + 2 (units)

The curve shows this simplified model over the labelled range. Read the exact point below; the sketch is not a measuring instrument.

3x + 2: 8

Which x makes the output 17? Explain the operations that lead there.

Now close the explanation and try the independent retest. Moving a slider alone does not check your understanding.

Start here if this is where you get stuck

Start here if moving terms changes signs unpredictably or brackets cause errors. This lesson repairs the one-unknown step before simultaneous or quadratic equations; it does not duplicate the Class 10 two-variable modelling lesson.

Solve x + 4 = 9. Name the operation on both sides and substitute your answer into the original equation.

Before you start

You will need: Signed arithmetic and the distributive law.

Attempt each task before opening a hint. If you need help, reveal the first hint, then the setup, then compare your written steps with the solution. Finish with the retests without referring back.

Three ideas to keep in view

Adding or subtracting the same quantity on both sides preserves equality. Multiplication or division by the same non-zero number also preserves it.

Expand a bracket by multiplying every term inside it. In 3(x−2), the constant contribution is −6.

An equation may have one solution, no solution or every value as a solution. After simplification, a false statement signals none and an identity signals all allowed values.

Try the worked example first

F-EQ-W1Undo operationsFocused practice

Solve 3x+2=17 and check the result.

Need a starting hint?

Undo the addition before undoing multiplication.

Still stuck? Reveal the setup

Subtract 2 from both sides to get 3x=15.

Show worked solution
  1. Isolate the product

    Both sides lose 2.

  2. Divide and check

    x=5 and 3(5)+2=17.

Answer: x=5

Before moving on: can you explain why your method works, as well as give the answer?

Your turn: three different checks

Write a method as well as an answer. The tasks change the reasoning, not just the numbers.

F-EQ-Q1BracketFocused practice

Solve 2(x−3)=10.

Need a starting hint?

You can divide both sides by 2 first.

Still stuck? Reveal the setup

x−3=5.

Show worked solution
  1. Divide

    The full left side is halved.

  2. Add

    Add 3 to both sides: x=8.

Answer: x=8

Before moving on: can you explain why your method works, as well as give the answer?

F-EQ-Q2Both sidesFocused practice

Solve 5x−4=2x+11.

Need a starting hint?

Gather the x terms on one side.

Still stuck? Reveal the setup

Subtract 2x, then add 4.

Show worked solution
  1. Collect

    3x−4=11, then 3x=15.

  2. Divide

    x=5; each original side is 21.

Answer: x=5

Before moving on: can you explain why your method works, as well as give the answer?

F-EQ-Q3No solutionFocused practice

Does 2(x+1)=2x+5 have a solution?

Need a starting hint?

Expand the bracket.

Still stuck? Reveal the setup

Subtract 2x from both sides.

Show worked solution
  1. Expand

    2x+2=2x+5.

  2. Compare

    The remaining statement 2=5 is false for every x.

Answer: No solution

Before moving on: can you explain why your method works, as well as give the answer?

Catch a likely mistake

A tempting claim: “A term changes sign simply because it crosses the equals sign.”

The shortcut hides the operation preserving equality and breaks down with brackets or division.

Close the examples and try again

These changed questions test whether you can reconstruct the method. If you use a hint, record where you got stuck and retry later. Completing this small set does not establish full chapter mastery.

F-EQ-R1Changed coefficientsIndependent retest

Solve 4x+3=27.

Need a starting hint?

Undo +3, then ×4.

Still stuck? Reveal the setup

4x=24.

Show worked solution
  1. Subtract

    27−3=24.

  2. Divide and check

    x=6; 4(6)+3=27.

Answer: x=6

Could you solve this without the earlier example? If not, revisit the first line where you got stuck.

F-EQ-R2IdentityIndependent retest

How many solutions does 3(x+2)=3x+6 have?

Need a starting hint?

Expand the left side.

Still stuck? Reveal the setup

Both sides become identical.

Show worked solution
  1. Expand

    3x+6=3x+6.

  2. Interpret

    This holds for every real x.

Answer: Every real x

Could you solve this without the earlier example? If not, revisit the first line where you got stuck.

Use the repair in your next task

Try the two retests with examples closed. If the same error returns, correct that step and retry later; this short practice is not a diagnostic score or a grade assessment.

Ask the learner to say the operation at each line and check the original equation. Do not treat a correct result from unexplained sign-changing as proof that the difficulty is resolved.

If the retests are independent, return to the problem that brought you here. The linked Class 10 application is optional for learners already studying that topic; younger learners should use their current school exercise.

Frequently asked questions

Can I always divide by an expression containing x?

Only if you know it is non-zero for the case being considered. Dividing by an expression that may be zero can lose valid solutions.

Can I print the questions and worked solutions separately?

Yes. Use the two print buttons above. The question sheet leaves working space and hides solutions; the worked-solutions option includes the solution steps. Your browser can save either view as a PDF.

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Further reading and official sources