Solving equations systematically

Using inverse operations and equivalent equations to solve one-step and two-step linear equations, including negative solutions.

Inverse operations

Example 1●

Solve $3x - 5 = 16$.

$3x = 21$

Add 5 to both sides.

$x = 7$

Divide both sides by 3.

Example 2●●

Solve $11 - 2a = 19$.

$-2a = 8$

Subtract 11 from both sides.

$a = -4$

Divide both sides by −2.

Solving 3x − 5 = 16 on a graph

The solution is the x-value where the line y = 3x − 5 meets the line y = 16.

Flashcards

Undo +5

Subtract 5 from both sides.

Solve $4x + 1 = 21$

$x = 5$

Order of undoing

Reverse order: undo $+$/$-$ before $\times$/$\div$.

Practice