Worked examples
Two examples
Example 1
Multiply: (x + 3)(x − 5)
- Each term by each term: x2, −5x, 3x, −15.
- Combine the x terms: −5x + 3x = −2x.
Answer: x2 − 2x − 15
Example 2
Multiply: (2x + 1)(x + 4)
- 2x2, 8x, x, 4.
- 8x + x = 9x.
Answer: 2x2 + 9x + 4
Where this is taught: Quiz 39: Polynomials and Factoring, “Multiplying two binomials”
The drill
Ten problems
This drill also has challenge problems. They use the same skill, set up the way the GED test sometimes sets up a problem, so that it looks new at first.
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.