Solving linear equations

Solving one-step and two-step linear equations with inverse operations, including negative solutions and checking.

Inverse operations

To solve $3x + 5 = 26$, undo the "$+5$" first, then the "$\times 3$".

Example 1●

Solve $3x + 5 = 26$.

$3x = 21$

Subtract 5 from both sides

$x = 7$

Divide both sides by 3

$3(7) + 5 = 26$ ✓

Check

Example 2●●

Solve $\dfrac{x}{4} - 3 = -5$.

$\dfrac{x}{4} = -2$

$x = -8$

Example 3●●

Solve $10 - 2x = 4$.

$-2x = -6$

$x = 3$

Flashcards

Undo order

Reverse of the order of operations: undo $\pm$ first, then $\times \div$.

$5x = -35$

$x = -7$

How to check

Substitute back into the original equation.

Practice