How do you divide #(x^3-2x^2-3x+2) / (x-1)#?

1 Answer
Oct 1, 2016

#"The Quotient Poly."=x^2-x-4#.

#"The Remainder="-2#.

Explanation:

We can perform the Long Division and get the Quotient and the

Remainder. But, here is another way to solve the Problem.

Suppose that, when #P(x)=x^3-2x^2-3x+2# is divided by

#(x-1)#, the Quotient Poly. is #Q(x)# and the remainder #R.# Note

that, since the divisor #9x-1)# is a Linear Poly., the Remainder has

to be a constant.

The well-known relation btwn. #P(x), Q(x), (x-1) and, R# is

given by, #P(x)=(x-1)Q(x)+R,# i.e.,

# x^3-2x^2-3x+2=(x-1)Q(x)+R........................(star)#

Sub.ing, #x=1" in "(star), 1-2-3+2=(1-1)Q(x)+R :. R=-2.#

Then, sub.ing #R=-2" in "(star), x^3-2x^2-3x+2=(x-1)Q(x)-2,#

#or, x^3-2x^2-3x+4=(x-1)Q(x)#

# rArr Q(x)=(x^3-2x^2-3x+4)/(x-1)#

#=(x^3-x^2-x^2+x-4x+4)/(x-1)#

#={x^2(x-1)-x(x-1)-4(x-1)}/(x-1)#

#={cancel((x-1))(x^2-x-4)}/cancel((x-1))#

#:. Q(x)=x^2-x-4#.

Enjoy Maths.!