Question

Разложите на множители: 1)81с^2-d^2+9c+d 2)25-m^2-12mn-36n^2

Answer 1

1) 81с^2 - d^2 + 9c + d = (9c-d)(9c+d) + (9c+d) = (9c+d)(9c-d+1)
2) 25 - m^2 - 12mn - 36n^2 = 25 - (m^2 + 12mn + 36n^2) = 25 - (m + 6n)^2 = (5 - m - 6n)(5 + m + 6n)