Which polynomial is a factor of $x^3 - 5x^2 + 11x - 10$?
A - HSC - SSCE Mathematics Extension 1 - Question 1 - 2017 - Paper 1
Question 1
Which polynomial is a factor of $x^3 - 5x^2 + 11x - 10$?
A.
x - 2
B.
x + 2
C.
11x - 10
D.
x^2 - 5x + 11
Worked Solution & Example Answer:Which polynomial is a factor of $x^3 - 5x^2 + 11x - 10$?
A - HSC - SSCE Mathematics Extension 1 - Question 1 - 2017 - Paper 1
Step 1
Evaluate potential factors
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
To determine which polynomial is a factor of the given polynomial, we need to test each option by using polynomial division or the factor theorem. The factor theorem states that for a polynomial f(x), if f(c)=0, then (x−c) is a factor of f(x).
Let's evaluate the options:
Option A: x−2
Substitute x=2 into the polynomial:
f(2)=23−5(22)+11(2)−10 =8−20+22−10=0
Hence, x−2 is a factor.
Option B: x+2
Substitute x=−2 into the polynomial:
f(−2)=(−2)3−5(−2)2+11(−2)−10\
eq 0$$
Thus, x+2 is not a factor.
Option C: 11x−10
This is not in the form of (x−c). We do not test this directly.
Option D: x2−5x+11
This is again not in a simple linear factor form; we'll skip its evaluation as we already found a valid factor.
Since in our evaluation, only option A yielded a value of zero, we have concluded that the correct answer is A: x−2.