Ответ:
- \(400-m^2=(20-m)(20+m)\);
- \(4x^2-25=(2x-5)(2x+5)\);
- \(2\frac{7}{9}f^2-1=\frac{25}{9}f^2-1=\left(\frac{5f}{3}-1\right)\left(\frac{5f}{3}+1\right)\);
- \(16d^2-81=(4d-9)(4d+9)\);
- \((x+1)^2-16=(x-3)(x+5)\);
- \(a^2-12a+36=(a-6)^2\);
- \(16m^2+24m+9=(4m+3)^2\);
- \(4mn+9m^2=m(4n+9m)\).
