PROBLEM concering POLYNOMIALS...?

Question

The question says this:

http://img238.imageshack.us/img238/1338/poy15zc9.png

My answer was:

http://img139.imageshack.us/img139/3785/poy152vy2.png

Obviously, it was wrong. How do you solve a problem like this?

Answer 1

For each root find a factor...

If root = r

then factor = (x - r)

Since the coefficient of x^3 is -18, multiply the whole thing by -18

-18(x + 1)(x - 2)(x - 8)

Answer 2

For each root, find a factor.
Use the factor theorem: If r is a zero of a polynomial
then x-r is a factor.
A polynomial with the given roots.
is (x+1)(x-2)(x-8) = x³-9x² +6x+16.
Since we want the coefficient of x² to be -18, just
double each coefficient:
The answer is 2x³-18x²+12x+32.
Here's another way:
Let's find a polynomial with the given roots
The coefficient of x² is minus the sum of the roots or -9
The coefficient of x is the sum of the roots taken 2
at a time = -2-8+16 = 6
The constant term is -the product of the roots or 16.
Putting it all together, we get the same answer as above.

Answer 3

hey, the oefficient of x^2 must be -18, not 18!
watch out
byeee^_^