F(x)=x.(x+1).(x+2).(a. x+b) Xét a, b để f(x)-f(x-1)=x.(x+1).(2x+1)

Shape a is congruent to shape , as shown by a reflection across the y-axis and then a translation down units. shape b is congruent to shape , as shown by a reflection across the y-axis and then a translation down units.