Wednesday

July 30, 2014

July 30, 2014

Posted by **alicia** on Thursday, March 7, 2013 at 10:17am.

- math -
**Reiny**, Thursday, March 7, 2013 at 10:23amlet f(x) = x^3-9x^2+16x-8

try x = ±1, ±2, ±4, ±8 , hoping to get f(x) = 0

wow, after one try ...

f(1) = 1 - 9 + 16 - 8 = 0

so x-1 is a factor

using synthetic division I had the other factor as

x^2 - 8x + 8

so x^2 - 8x + 8 = 0

I will use completing the square , since the middle term is even

x^2 - 8x + 16 = -8 + 16

(x-4)^2 = 8

x-4 = ±√8 = ± 2√2

x = 4 ± 2√2 or x = 1

**Related Questions**

Precalculus - "Show that x^6 - 7x^3 - 8 = 0 has a quadratic form. Then find the ...

Algebra II - Which describes the number and type of roots of the equation x^2 -...

Pre-cal - let P(x)=2x^4-x^3+13^2-8x-24. Use synethetic division to show that x+1...

maths2 - Use the discriminant to determine the number of real roots the equation...

mathematics - Use the discriminant to determine the number of real roots the ...

Math - Which describes the number and type of roots of the equation x^2-625=0? A...

math - Having a lil problem Prove that the roots of ax^2 + (a + b)x+b are real ...

Math - Determine for what value(s) of d the quadratic equation 5x^2-10x+d = 0 ...

how many solutions are real? - hi, I am stuck on this question. y=x^2+4x and y^2...

Math - A polynomial function f(x) has degree 6 and has real coefficients. It is ...