Algebra
Solving linear equations
An equation states that two expressions have the same value. Keep that equality by applying the same operation to both sides. Undo addition or subtraction first, then multiplication or division.
To solve 4x + 7 = 31, subtract 7 from both sides to obtain 4x = 24. Divide both sides by 4: x = 6. Check by substituting: 4 × 6 + 7 = 31.
When brackets appear, expand them before collecting like terms. For 3(x − 2) = 15, divide both sides by 3 to obtain x − 2 = 5, then add 2 to obtain x = 7.
Apply the same operation to both sides, and substitute your answer to check it.
Sign in to save progress