Worked examples
Two examples
Example 1
Multiply out: (x + 4)2
- Squaring means (x + 4)(x + 4).
- First squared, twice the product, last squared: x2 + 8x + 16. Not just x2 + 16.
Answer: x2 + 8x + 16
Example 2
Multiply: (x − 6)(x + 6)
- The middle terms, −6x and 6x, cancel.
- First squared minus last squared.
Answer: x2 − 36
Where this is taught: Quiz 39: Polynomials and Factoring, “Two patterns worth noticing”
The drill
Ten problems
How many:
Type your answer like 3x^2 - 2x + 5: use ^ for a power, and write like terms together. Then press Check my answers at the bottom.Write each answer on the line. The answer key, with the reasoning, is on the last page.