Equations & inequalities
One-step equations
ALEKS placementTEAS math
Undo the one operation attached to the variable, on both sides.
What this covers
- Name the operation currently applied to the variable.
- Apply its inverse to both sides.
- Simplify each side.
- Substitute your answer back to check.
Worked example
Worked example
Solve x - 6 = 9.
- x−6+6=9+6Subtraction is undone by addition, on both sides.
- x=15The -6 and +6 cancel, leaving x alone.
Another worked example
Solve x/4 = −3.
- 4⋅4x=4(−3)x is divided by 4, so multiply both sides by 4.
- x=−12Check: −12 ÷ 4 = −3.
A common mistake
A mistake Lemma catches
From −3x=12
x=−36x=−4
“You multiplied 12 by -3, but x is multiplied by -3 on the left — undoing a multiplication means dividing both sides by -3.”
Try one
Sample problem
Solve for x.
x−9=−1Practice one-step equations free
No account, no email. Every line you type is checked by the same computer algebra system as the worked example above.
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