1. (a-b)(a+b)=a²-b²
2. (a-2)(a+2)=a²-4
3. (1-b)(1+b)=1-b²
4. (3a-b)(3a+b)=9a²-b²
5. (3x-1)(3x+1)=9x²-1
6. (13m-11n)(13m+11n)=169m²-121n²
7. (10p+7q)(7q-10p)=79q²-100p²
8. (4-5y)(5y+4)=16-25y²
9. (a+2)²=a²+4a+4
10. (3b-1)²=9b²-6b+1
11. (x-8)²=x²-16x+64
12. (1+4y)²=1+8y+16y²