Q13/060) a,b,c,d are integers given :a+b=c, b+c=d , c+d=a now if b>0, find max(a+b+c+d)

by solving we get

a = -3b,
c = -2b
d = -b

so sum = a + b + c + d = - 5b

it is largest when b ls smallest

b = 1 as b > 0 and integer

so largest sum = - 5