Equivalent Expressions

Equivalent Expressions

Equivalent expressions look different but have the same value for every allowed input. You can use the distributive law to expand a bracket or factor a common part. Test your result with a number, but remember that one successful test supports an idea; algebraic steps show why it is always true.

Worked example

$3(x+4)=3x+12$. If $x=2$, both sides equal 18, because the 3 multiplies both parts inside the bracket.

Exam method

1. Identify the operation outside the bracket. 2. Apply it to every term inside. 3. Test one value and check that each original part was used once.