Question
There is an error in the student work shown below:
Question: Divide (x^3-8)/(x-2)
The student did long division and the got x^2 remainder -6+2x^2
Question: Divide (x^3-8)/(x-2)
The student did long division and the got x^2 remainder -6+2x^2
Answers
Reiny
Yup, there is an error!
However, it is a poor question which asks to explain somebody's error
Correct way:
(x^3-8) = (x-2)(x^2 + 2x+ 4)
so ...
(x^3-8)(x-2)
= (x-2)(x^2 + 2x+ 4)/(x-2)
= x^2 + 2x + 4 , x ≠ 2
However, it is a poor question which asks to explain somebody's error
Correct way:
(x^3-8) = (x-2)(x^2 + 2x+ 4)
so ...
(x^3-8)(x-2)
= (x-2)(x^2 + 2x+ 4)/(x-2)
= x^2 + 2x + 4 , x ≠ 2