S obzirom na zadanu vrijednost s promjenom
# 4 (1 + y) x ^ 2-4xy- (1-il) #
# => 4 (1 + y) 2-2 x ^ (1 + y) x 2 + (1-il) x- (1-il) #
# => 2 (1 + y) x (2 x-1) + (1-il) (2 x-1) #
# => (2 x-1), (2 (1 + y) + x (1-il)) = 0 #
Stoga # X = 1/2 #
provjeravanje
# 4 (1 + y) x ^ 2-4xy- (1-il) #
# = 4 (1 + y) (1/2) ^ 2-4 (1/2) y- (1-il) #
# = 1 + y-2y-1 + y = 0 #