Algebra Review

Section 1Algebra basics

In algebra, letters stand for numbers. An expression like 3x + 5 has no equals sign, so it can be simplified but not solved. An equation like 3x + 5 = 20 can be solved because it has an equals sign.

Section 2Like terms

Like terms have the same letter part, such as 4x and 7x. You can add them to get 11x. Watch out: 4x and 4y are not like terms because the letters are different.

Section 3Solving equations

To solve an equation, do the opposite operation to both sides. Here's the trick: keep the equation balanced like two sides of a scale. If you subtract 5 from one side, subtract 5 from the other side too.

Section 4Checking answers

After solving, substitute your answer back into the original equation. If both sides match, your answer works. This is a powerful way to catch small sign errors.