SOLUTION: ----------- ----------- ----------- ----------- ----------- ----------- ----------- ----------- ----------- ----------- ----------- --- Q10 Let us consider a function f (x) = x

Algebra ->  Numeric Fractions Calculators, Lesson and Practice -> SOLUTION: ----------- ----------- ----------- ----------- ----------- ----------- ----------- ----------- ----------- ----------- ----------- --- Q10 Let us consider a function f (x) = x      Log On


   

Question 1119196:
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Q10 Let us consider a function f (x) = x^3-x^2-x-8
If f (u) = – 8, how many real values of u are there?
A) 0
B) 1
C) 2
D) 3
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Answer by greenestamps(13200) About Me  (Show Source):
You can put this solution on YOUR website!


x%5E3-x%5E2-x-8+=+-8
x%5E3-x%5E2-x+=+0
x%28x%5E2-x-1%29+=+0

x=0 is a solution; and the discriminant of the quadratic factor is positive, so the quadratic factor has two roots.

So there are 3 real solutions for f(u) = -8.