SOLUTION: which of the following is not a solution to the equation: F(x) = x^5 + 5x^3 - 36x? a) 0 b) +/- 2 c) +/- 3 d) +/- 3i

Algebra ->  Functions -> SOLUTION: which of the following is not a solution to the equation: F(x) = x^5 + 5x^3 - 36x? a) 0 b) +/- 2 c) +/- 3 d) +/- 3i      Log On


   

Question 1004735: which of the following is not a solution to the equation: F(x) = x^5 + 5x^3 - 36x?
a) 0
b) +/- 2
c) +/- 3
d) +/- 3i
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

+F%28x%29+=x%5E5+%2B+5x%5E3+-+36x....factor completely
+F%28x%29+=x%28x%5E4+%2B+5x%5E2+-+36%29
+F%28x%29+=x%28x%5E4+%2B+9x%5E2-4x%5E2+-+36%29
+F%28x%29+=x%28%28x%5E4+%2B+9x%5E2%29-%284x%5E2%2B+36%29%29
+F%28x%29+=x%28x%5E2%28x%5E2+%2B+9%29-4%28x%5E2%2B+9%29%29
+F%28x%29+=x+%28x%5E2%2B9%29+%28x%5E2-4%29+
+F%28x%29+=x+%28x%5E2%2B9%29+%28x-2%29+%28x%2B2%29
zeros:
+0+=x+%28x%5E2%2B9%29+%28x-2%29+%28x%2B2%29
+0+=x
if +0+=x%5E2%2B9=>x%5E2=-9=>x=sqrt%28-9%29=>x=3i and x=-3i
if +0+=+x-2 =>x=2
if +0+=+x%2B2=>x=-2

so, c) +/- 3 is not a solution to the equation