1) в скобках
((5m+2)(5m+2) -(5m-2)(5m-2)) /(5m-2)(5m+2) =(25m² +20m+4 -(25m²-20m+4)) /(5m-2)(5m+2) =(25m²+20m+4 -25m²+20m-4) /(5m-2)(5m+2) =40m /(5m-2)(5m+2)
2) 12-75m² =3(4-25m²) =3(2-5m)(2+5m) = -3(5m-2)(5m+2)
3) при делении дробь переворачиваем и будет умножение
40m/(5m-2)(5m+2) *(-3(5m-2)(5m+2)/20m = -40m*(5m -2)(5m +2) /20m*(5m -2)(5m +2) = -2
ответ: -2