1)(√5-а)*(√5+а)
2)(√z-√7)*(√z+√7)
3)(b+√c)*(√c-b)
4)(√2m+√11n)*(v11n-√2m)

Решение1)(√5-а)*(√5+а) = (√5)² - a² = 5 - a²2)(√z-√7)*(√z+√7) = (√z)² - (√7)² = z - 73)(b+√c)*(√c-b) = (√c)² - b² = c - b²4)(√2m+√11n)*(v11n-√2m) = (√11n)² - (√2m)² = 11n - 2m