Which of the following is a factor of f(x) = 4x3 + 11x2 - 75x + 18?
(x - 3), (x + 3), (x - 1/3), (x + 1/3)
Solution:
The factor of the polynomial f(x) is a term like (x - k) and only if f(k) = 0.
Let us test this condition for all the options given in the question.
To determine the factor we can proceed by considering the given options.
Given: Polynomial f(x) = 4x3 + 11x2 - 75x + 18
From option (x - 3),
f(3) = 4(3)3 + 11(3)2 - 75(3) + 18
f(3) = 4(27) + 11(9) - 75(3) + 18
f(3) = 108 + 99 - 225 + 18
f(3) = 225 - 225
f(3) = 0
Condition is satisfied.
From option (x + 3)
f(-3) = 4(-3)3 + 11(-3)2 - 75(-3) + 18
f(-3) = 4(-27) + 11(9) - 75(-3) + 18
f(-3) = -108 + 99 + 225 + 18
f(-3) = 342 - 108
f(-3) = 252
f(-3) ≠ 0
Condition is not satisfied.
Therefore, (x - 3) is the factor of f(x) = 4x3 + 11x2 - 75x + 18.
Which of the following is a factor of f(x) = 4x3 + 11x2 - 75x + 18?
Summary:
The factor of f(x) = 4x3 + 11x2 - 75x + 18 is (x - 3). The factor of the polynomial f(x) is a term like (x - k) and only if f(k) = 0.
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