Mathematics · Grades 8–11
Expand a binomial square
The middle term is twice the product, not zero.
The key idea
The middle term is twice the product, not zero.
(x + a)² = x² + 2ax + a²
Worked examples
Expand (6x + 24)². What is the coefficient of x?
2 × 6 × 24 = 288
288
Expand (1x + 10)². What is the coefficient of x?
2 × 1 × 10 = 20
20
Try it yourself
Expand (8x + 4)². What is the coefficient of x?
Expand (5x + 12)². What is the coefficient of x?
Check your understanding
Answers and marking notes
- 64
2 × 8 × 4 = 64
- 120
2 × 5 × 12 = 120
Further reading and review references
These are reference links, not copied exercises, institutional endorsement or proof of independent review.
Learning preview · teacher review required. Grade bands are approximate, not official curriculum alignment.