i.y=x^2 -4x
y'=2x-4
increasing when y'>0 at x>2
ii.y=x^2 -2x-3
y'=2x-2
increasing when y'>0 at x>1
iii.y=12+4x-x^2
y'=4-2x
increasing when y'>0 when x<2
iv.y=x^3 +3x^2-5
y'=3x^2+6x
increasing when y'>0 at x<-2 or x>0
v.y=x^3-6x^2-15x+8
y'=3x^2-12x-15
increasing when y'>0 at x<-1 or x>5
vi.y=24x-3x^2-x^3
y'=24-6x-3x^2
increasing when y'>0 at -4<x<>2
