y=abs(x)
y=abs(x+2)
y=abs(x)+2
y=abs(x-3)
y=abs(x)-3
y=abs(1-x)
y=1-abs(x)
y=abs(3-2x)
y=3-abs(2x)
y=-abs(x)
y=-abs(x)+1
y=-abs(x)-2
y=x+abs(x)
y=x-abs(x)
y=abs(x)-x
y=2abs(x)
y=abs(2x)
y=5abs(x)
y=abs(5x)
y=0.2abs(x)
y=abs(0.2x)
y=abs(-x)
y=abs(-4x)
y=-x-abs(x)