Go over this with me please, I forgot how to do it.
Solve the polynomial equation.
15x^3-119x^2-10x+16=0
2 answers
nvm... i figured out how, you factor then solve :)
let f(x) = 5x^3 - 119x^2 - 10x + 16
now try some f(x) , where x = ±1, ±2, ±4, ±8 ...
hopefully to get a zero
took some some, but f(8) = 0
so (x-8) will be a factor
now by synthetic division , I got
15x^3-119x^2-10x+16
= (x-8)((15x^2 + x - 2) = 0
which factors further to
(x-8)(3x - 1)(5x + 2) = 0
x = 8, or x = 1/3 or x = -2/5
now try some f(x) , where x = ±1, ±2, ±4, ±8 ...
hopefully to get a zero
took some some, but f(8) = 0
so (x-8) will be a factor
now by synthetic division , I got
15x^3-119x^2-10x+16
= (x-8)((15x^2 + x - 2) = 0
which factors further to
(x-8)(3x - 1)(5x + 2) = 0
x = 8, or x = 1/3 or x = -2/5
1 answer