Multi-Step Equations
Introduction
Multi-step equations appear when solving requires more than one inverse operation, and often when variables appear on both sides of the equation.
Because you already understand Two-Step Equations, this article builds on that knowledge and introduces:
- Combining like terms
- Distributing
- Moving variable terms to one side
- Keeping equations balanced through multiple steps
The goal is to help you confidently solve equations such as:
- $3x + 4 = 2x - 5$
- $5(x - 2) = 3x + 6$
- $\frac{x + 4}{3} = 2x - 1$
What Are Multi-Step Equations?
A multi-step equation is any equation that requires three or more operations to isolate the variable.
Common features include:
- Variables on both sides
- Parentheses requiring distribution
- Fractions requiring clearing denominators
- Like terms that must be combined
Examples:
- $4x - 7 = 2x + 5$
- $3(x + 2) - 4 = 2(x - 1)$
- $\frac{2x - 3}{5} + 1 = x$
General Strategy
To solve multi-step equations, follow this reliable sequence:
- Remove parentheses
- Use distribution: $a(b + c) = ab + ac$
- Clear fractions (optional but helpful)
- Multiply both sides by the least common denominator (LCD)
- Combine like terms
- Move variable terms to one side
- Add/subtract to collect all $x$ terms together
- Move constants to the other side
- Isolate the variable
- Divide or multiply as needed
- Check your solution
- Substitute back into the original equation
Worked Examples
Example 1: $3x + 4 = 2x - 5$
- Subtract $2x$ from both sides
→ $x + 4 = -5$ - Subtract $4$
→ $x = -9$
Example 2: $5(x - 2) = 3x + 6$
- Distribute
→ $5x - 10 = 3x + 6$ - Subtract $3x$
→ $2x - 10 = 6$ - Add $10$
→ $2x = 16$ - Divide by $2$
→ $x = 8$
Example 3: $\frac{x + 4}{3} = 2x - 1$
- Multiply both sides by $3$
→ $x + 4 = 6x - 3$ - Subtract $x$
→ $4 = 5x - 3$ - Add $3$
→ $7 = 5x$ - Divide
→ $x = \frac{7}{5}$
Common Mistakes to Avoid
- Forgetting to distribute a negative sign
- Moving constants and variable terms in the wrong direction
- Not multiplying every term when clearing fractions
- Combining unlike terms (e.g., $3x + 4$ cannot become $7x$)
Calculator
Solving equations
- As with two-step equations, multi-step equations are solved via the $\operatorname{solveLinear}()$ function
solveLinear('3x + 4 = 2x - 5') solveLinear('(x + 4)/3 = 2x - 1')
Exercises
- Solve the equation: $4x - 3 = 2x + 9$
- Solve: $5(x + 1) = 3x + 11$
- Solve: $\frac{2x - 5}{3} = x + 1$
- Solve: $7x + 4 = 3(2x - 1)$
- Solve: $6 - 2(x - 3) = 4x + 8$
- Solve: $\frac{x + 2}{4} + 3 = x$
- Solve: $9x - 5 = 2(4x + 1)$
- Solve: $3(x - 4) + 2 = x - 10$