For each x intercept the corresponding factor can be deduced. For x intercepts given at 1,2,3 , the equation can be written as
y= (x-1) (x-2) (x-3)
Because x=1 therefore x-1=0 , similarly x=2 , x-2=0 and , x=3 , x-3=0
or
y= x²+2x-3 (x-3)
or
y= x³+2x²-3x-3x²-6x+9
y= x³-x²-9x+9
