Linear equations

Solve for x

Enter a complete equation and follow the same operation on both sides until x is isolated. Restrictions and special cases remain visible beside the answer.

Use the math keyboard or your device keyboard.

Remove the constant, clear the denominator, and divide by the coefficient without changing the equality.

x=10x=10
Conditions
  • x is a real variable.
  • Both sides are defined for every value considered.
  • The input is a linear equation after valid simplification.

Steps

  1. Remove the outside constant Subtract 1 from both sides.3(x2)4=6\frac{3(x-2)}{4}=6
  2. Clear the denominator Multiply both sides by 4.3(x2)=243(x-2)=24
  3. Undo the multiplication Divide both sides by 3.x2=8x-2=8
  4. Isolate x Add 2 to both sides.x=10x=10
Independent check

Substitution gives 3(10-2)/4+1=6+1=7, which matches the right side.

What this solve-for-x covers

To solve for x, simplify each side, move variable terms to one side, move constants to the other, and divide by the remaining coefficient. An identity has infinitely many solutions, while a contradiction has no solution.

One-step equations

Undo a single addition, subtraction, multiplication, or division.

Examples: x+8=13, 5x=35

Multi-step equations

Distribute and combine like terms before isolating x.

Examples: 4(x+1)=3x+9, 2(x-3)+5=11

Fractional equations

Clear constant denominators with a common nonzero multiplier, then solve the equivalent equation.

Examples: x/5-2=3, (x-1)/3=(x+5)/6

Variables on both sides

Collect x-terms to reveal one solution, an identity, or a contradiction.

Examples: 5x-4=2x+11, 5x+2=5x+2, 4x-1=4x+3

Enter enough information for one clear task

  1. 1
    Write both sides completely

    Use an equals sign and parentheses around every grouped numerator or distributed expression.

  2. 2
    Simplify before isolating

    Distribute and combine like terms on each side so the coefficient of x is clear.

  3. 3
    Keep the equation balanced

    Every addition, subtraction, multiplication, or division used to isolate x must be applied to both sides.

  4. 4
    Substitute into the original

    A valid solution makes the original left and right sides defined and equal, not merely the final transformed line.

Examples to try

Use these examples to recognize the method, compare equivalent forms, and check your own work.

Addition and division

Subtract 5 and divide by 2.

2x+5=172x+5=17

Expected result

x=6x=6

Negative coefficient

Subtract 7, then divide by negative 3.

73x=87-3x=-8

Expected result

x=5x=5

Variable on both sides

Distribute, subtract 3x, and subtract 4.

4(x+1)=3x+94(x+1)=3x+9

Expected result

x=5x=5

Fraction coefficient

Add 2 and multiply by 5.

x52=3\frac{x}{5}-2=3

Expected result

x=25x=25

Fractions on both sides

Multiply by 6 and solve the resulting linear equation.

x13=x+56\frac{x-1}{3}=\frac{x+5}{6}

Expected result

x=7x=7

Identity

Subtracting matching sides leaves a true statement.

5x+2=5x+25x+2=5x+2

Expected result

xRx\in\mathbb{R}

Contradiction

Subtracting 4x leaves the false statement -1=3.

4x1=4x+34x-1=4x+3

Expected result

\varnothing

Clear two denominators without losing balance

The least common denominator is 6. Multiplying the entire equation by 6 removes both denominators in one valid step.

23(x+6)x2=5\frac{2}{3}(x+6)-\frac{x}{2}=5
  1. 1
    Multiply every term by 6

    Apply the same nonzero multiplier to both sides.

    4(x+6)3x=304(x+6)-3x=30
  2. 2
    Distribute and combine

    Expand 4(x+6), then combine the x-terms.

    4x+243x=304x+24-3x=30
  3. 3
    Isolate x

    The left side is x+24, so subtract 24 from both sides.

    x=6x=6
x=6x=6

Verification: The original left side becomes (2/3)(12)-6/2=8-3=5, equal to the right side.

Common mistakes and how to fix them

Changing only one side

Problem: Subtract 4 from the left side but leave the right side unchanged.

Why it matters: That creates a different equation rather than an equivalent one.

Better approach: Write the same operation on both sides before simplifying.

Clearing only one denominator

Problem: Multiply one fractional term by the common denominator and ignore the other terms.

Why it matters: A multiplier applied to an equation must multiply every term on both sides.

Better approach: Use parentheses around each side, then distribute the common denominator to every term.

Treating every linear equation as one-solution

Problem: Report x=0 after the x-terms cancel.

Why it matters: Cancellation can leave a true identity or a false contradiction.

Better approach: Classify a true statement as all real solutions and a false statement as no solution.

Dividing by the wrong sign

Problem: From -3x=-15, report x=-5.

Why it matters: A negative divided by a negative is positive.

Better approach: Write x=(-15)/(-3)=5 and verify it in the original equation.

Checks, assumptions, and limits

How results are checked

  • The isolated value is substituted into the original equation.
  • Identity and contradiction cases are classified from the final truth value.
  • Each denominator is checked before and after clearing fractions.

When to stop and revise the input

  • The equation must be linear after valid simplification for this focused calculator.
  • Variable denominators require explicit domain restrictions and may produce excluded candidates.
  • An expression without an equals sign does not define a solve-for-x task.

Solve for x FAQ

What does it mean to isolate x?

It means writing an equivalent equation with x alone on one side. Each operation used to reach that form must preserve the same solution set.

Can a linear equation have no solution?

Yes. If the variable terms cancel and leave a false statement, such as -1=3, no value of x satisfies the original equation.

When does a linear equation have infinitely many solutions?

If simplification produces a true identity, such as 2=2, both sides represented the same expression. Every real x allowed by the original domain is then a solution.

Why should I clear fractions first?

Multiplying by a common nonzero denominator often makes the equation easier to read. It is optional, and any original denominator restrictions still apply.

How do I check a value of x?

Replace x with the value in the original equation and simplify both sides independently. The check succeeds only when both sides are defined and equal.

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Created by Mathos AI. Methods, conditions, and checks are shown so you can review the mathematical reasoning.