If a, b, c and d are distinct pairwise co-prime positive integers such that a^2 + b^2 = c^2 + d^2, find the lowest possible value of a + b + c + d?
If a, b, c are three real numbers such that a + b + c = 7, a^2 + b^2 + c^2= 35 and a^3 + b^3 + C^3 = 151. Find the value of abc?
If
a+b=8, a+c=13, b+d=8, c-d=6
Then
a, b, c, d = ??
