The expression \(a+b+c+d=30\), where \(a,b,c,d \) are integers.
To maximize the value of \((a−b)^2+(a−c)^2+(a−d)^2\), each bracket should have the least possible value.
Choosing the values \((a,b,c,d)=(8,8,7,7),\) the given expression evaluates to 2, and it cannot have a smaller value.