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Literal Equation

A literal equation is an equation that contains two or more variables (letters). Solving a literal equation means rearranging it to get one specific variable alone on one side, expressed in terms of the remaining variables.

A literal equation is an equation in which at least two distinct variables appear. To solve a literal equation for a given variable means to isolate that variable on one side of the equation using algebraic operations, expressing it as a function of the other variables and any constants present. Many well-known formulas, such as A=lwA = lw or d=rtd = rt, are literal equations.

Worked Example

Problem: Solve the equation 3x+2y=123x + 2y = 12 for yy.
Step 1: Subtract 3x3x from both sides to begin isolating yy.
2y=123x2y = 12 - 3x
Step 2: Divide both sides by 2 to get yy alone.
y=123x2y = \frac{12 - 3x}{2}
Step 3: Simplify by splitting the fraction if desired.
y=632xy = 6 - \frac{3}{2}x
Answer: y=632xy = 6 - \dfrac{3}{2}x

Why It Matters

Literal equations show up constantly in science and everyday math. When you rearrange d=rtd = rt to get t=drt = \frac{d}{r}, you're solving a literal equation — figuring out travel time from distance and rate. Being comfortable with this skill is essential for physics, chemistry, and any field where you need to rework a formula to find the quantity you're after.

Common Mistakes

Mistake: Treating the other variables like numbers and trying to combine unlike terms.
Correction: Each variable represents a different quantity. You cannot combine 3x3x and 2y2y into 5xy5xy or anything similar. Only like terms (same variable, same exponent) can be combined.
Mistake: Forgetting to apply an operation to every term on both sides.
Correction: When you divide both sides by a value, you must divide every term — not just one. For example, dividing 2y=123x2y = 12 - 3x by 2 means both 1212 and 3x-3x get divided by 2.

Related Terms

  • EquationA literal equation is a specific type of equation
  • VariableLiteral equations contain two or more variables
  • FormulaMost formulas are literal equations
  • SolveSolving means isolating the target variable