That is, (n / M + 5) * (n / m-5) = - 1, how to get n & # 178; = 25-m & # 178;

That is, (n / M + 5) * (n / m-5) = - 1, how to get n & # 178; = 25-m & # 178;

From the square difference formula
(n/m+5)*(n/m-5)=-1
n^2/(m^2-25)=-1
n^2=-(m^2-25)
n^2=25-m^2