SAT Algebra and Advanced Math Practice Questions

Algebra / Linear Equations One Variable

Linear Equations in One Variable

Linear equations in one variable ask for the value of a single unknown that makes an equation true. Common moves include distributing, combining like terms, clearing fractions, and using inverse operations.

Least you need to know

  • A linear equation in one variable can often be solved by isolating the variable.
  • Equivalent operations may be applied to both sides of an equation.
  • Some linear equations have one solution, no solution, or infinitely many solutions.

Key notation

  • x — The unknown value in a one-variable equation

Worked example

  • Consider $3(x-2)+5=20$.
  • Distribute: $3x-6+5=20$.
  • Combine like terms: $3x-1=20$.
  • Add 1 to both sides: $3x=21$.
  • Divide by 3: $x=7$.

Common mistakes

  • Distribute to every term inside parentheses.
  • When clearing fractions, multiply every term on both sides.
  • A variable that cancels out may indicate no solution or infinitely many solutions.

How to recognize it

  • The problem asks for the value of one variable.
  • The equation can be simplified to a form such as $ax+b=c$ or $ax+b=cx+d$.

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Linear Equations in One Variable

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