Max, min (nếu có): A = | x | + 10; B = (| x |+ 10) / (| x | + 2); C = (100.| x | + 250) / (| x | + 2)

A = | x | + 10
B = ( | x |+ 10 ) / ( | x | + 2 )
C = ( 100 . | x | + 250 ) / ( | x | + 2 )
D = ( 100 . | x | - 250 ) / ( | x | + 2 )
E = | x - 1 | + | x - 2y + 3 z + 4 | + ( x + y - z + 10 )² + 50