Solving linear equations

Use inverse operations to get the unknown on its own, keep the equation balanced, and always check your answer.

阅读约 1 分钟更新于 2026年10月18日作者：Sumzo team审核：Sumzo team

An equation says two expressions are equal. A linear equation has the unknown only to the first power, like $3x + 5 = 20$ . To solve it, undo what has been done to $x$ , doing the same thing to both sides so the equation stays balanced.

例题

A two-step equation

Solve $3x + 5 = 20$ .

显示解题过程

Subtract 5 from both sides. $3x = 15$
Divide both sides by 3. $x = 5$
Check by substituting. $3(5) + 5 = 20 \checkmark$

答案： $x = 5$

已由 Sumzo 数学引擎核验

Brackets and unknowns on both sides

Expand any brackets.
Collect the $x$ terms on one side and the numbers on the other.
Divide by the coefficient of $x$ .

例题

Brackets and x on both sides

Solve $3(x - 2) = x + 4$ .