Topic explanation

Standard explanation

When you solve a rational equation, a root that hits an excluded value is extraneous. Throw it away. Checking is not optional.

Key points

• extraneous
• zeros of every original bottom
• cancelled still excluded
• keep the ideas separate
• Equations Later: When you solve a rational equation, a root that hits an excluded value is extraneous. Throw it away.
• WHAT — EQUATIONS LATER: When you solve a rational equation, a root that hits an excluded value is extraneous. Throw it away.
• HOW — Use the idea: Identify what is given, select this topic's rule or evidence, apply it one step at a time, and check
• CORE UNDERSTANDING: When you solve a rational equation, a root that hits an excluded value is extraneous. Throw it away.

Labelled diagram