ndehost 1.  (4b+1)(1-4b)=4b-16b^2+1-4b=-16b^2+1
2.  (5m+2)(2-5m)=10m-25m^2+4-10m=-25m^2+4
3. (13c−11d)(13c+11d)=169c^2+143cd−143dc−121d^2=169c^2−121d^2 4. (8m-9n)(8m+9n)=64m^2+72mn−72nm−81n^2=64m^2−81n
5. (c+2)(c-3)=c^2+c(−3)+2c−6=c^2−c−6
6. (2a-1)(3a+4)=6a^2+8a−3a−4=6a^2+5a−4
7. (5x-2y)(4x-y)=20x^2−5xy−8yx+2y^2=20x^2−13xy+2y^2
8. (a-2)(a^2-3a+6)=a^3+a^2(−3)+6a−2a^2+6a−12=a^3−5a^2+12a−12