Intro to Expressions and Equations

One-Step Equations

Solve an equation using one inverse operation: x + 5 = 12 → subtract 5 → x = 7.

Example

Undo addition by subtracting the same amount from both sides.

highlighted = computed this step

Step 1 — Set up

Set up the expression.

x+5=12x+ 5 = 12
Start balancedx + 512both sides start equal

Step 2 — Subtract from both sides

Subtract 5 from both sides.

x+5−5=12−5x+ 5 - \hl{5} = 12 - \hl{5}
Subtract the same amount from both sidesx + 5 - 512 - 5same operation keeps the scale level

Step 3 — Simplify

Simplify both sides: 12 - 5 = 7.

x=12−5=7x = 12 - 5 = \hl{7}
Both sides simplifyx7x is alone on the left

Step 4 — Check

Check the solution: 7 + 5 = 12.

7+5=127 + 5 = \hl{12}
Check the answer in the original equation7 + 512the original equation balances

Step 5 — Result

Read the final result.

x=7x = 7
x = 7x7x is alone on the left
one-step-equation To solve a one-step equation: - Identify the operation on x. - Apply the inverse to both sides. - Verify by substituting back.