Homework Help: trig

Posted by Bradley on Monday, June 2, 2008 at 9:19pm.

The equation f(x) = 3x^3 + 10x^2 - 16x - 32 has a root at x = -4

a) Find the depressed equation using synthetic division and the root given. Factor out any constants that may appear.

b) Factor the depressed equation (which is now a quadratic) using any method EXCEPT synthetic division.

c) List all the roots for f(x)

trig - Damon, Monday, June 2, 2008 at 9:51pm
They told you that x = -4 was a root so (x+4) is a factor so divide 3x^3 + 10x^2 - 16x - 32 by (x+4)

I get
3 x^2 - 2 x - 8

Factor that
3 * 1 factors 3
8*1 or 2*4 factors 8
so try 2 and 4
(3x -2)(x+4), nope
(3x-4)(x+2) close
(3x+4)(x-2) aha
so all the roots are
-4
-4/3
+2

Answer this Question

Related Questions

algebra - The equation f(x) = 3x^3 + 10x^2 - 16x - 32 has a root at x = -4 a) ...
Pre Algebra - Please help me with some problems. Thank you! Solve the equation ...
math - solve and check each of the following quadratic equation (1)x^2+16x=36 (2...
Math - 5(-3x - 2) - (x - 3) = -4(4x + 5) + 13 Answer Multiply factors. -15x - 10...
Math-find roots - 1.One root of each equation below is the same for both ...
Math - factor each expression completely. if possible. Just checkin the * Ones 1...
trig - if one of a quadratic equation is 1/2-2i, what is the equation. the other...
Algebra - 69: 16x^2+8x-3. I inserted this into the quadratic formula and got -8...
college math - I'm hoping I did thesse right. Solve each quadratic equation...
precal - when i do the quadratic equation i get -17 plus or minus the square ...

For Further Reading

First Name:
School Subject:
Answer: