Select all of the roots of x3 + 2x2 - 16x - 32.
-1, -2, -4, 1, 4, 5
Solution:
Given, the equation is x3 + 2x2 - 16x - 32.
We have to find all the roots of the equation.
Taking out common terms,
x3 + 2x2 - 16x - 32 = x2(x + 2) - 16(x + 2)
= (x2 - 16)(x + 2)
We know, (a2- b2) = (a - b)(a + b)
So, (x2 - 16) = (x - 4)(x + 4)
Now, x3 + 2x2 - 16x - 32 = (x + 2)(x - 4)(x + 4)
To find the roots,
⇒ (x + 2) = 0
x = -2
⇒ (x - 4) = 0
x = 4
⇒ (x + 4) = 0
x = -4
Therefore, the roots of the equation are -2, -4 and 4.
Select all of the roots of x3 + 2x2 - 16x - 32.
Summary:
The roots of the equation x3 + 2x2 - 16x - 32 are -2, -4 and 4.
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