Posted by **shannon** on Wednesday, May 26, 2010 at 12:21am.

p(x)=5x^3-4x^2+20-16

use synthetic division to show that x=2i is a zero of p(x)

- calculus -
**Reiny**, Wednesday, May 26, 2010 at 7:03am
Your function, which I will assume was to be

p(x) = 5x^3 - 4x^2 + 20x - 16 , factors very nicely by grouping

p(x) = 5x^3 - 4x^2 + 20x - 16

= x^2(5x-4) + 4(5x-4)

= (5x-4)(x^2 + 4)

so the zeros are

x = 4/5 and x = ± 2i

Using synthetic division for this expression is totally out of place.

- calculus -
**jonathan**, Tuesday, September 25, 2012 at 2:57pm
lim x¨‡ 2x 3 +5x 2 −x 3 =

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