Question

PLEASE HELP!!
Solve 125x^3 - 27

We're doing cubics today and I know that first we have to factor them out and I got:
(5x-3)(25x^2+15x+9) and we are supposed to get that trinomial.
But then we have to solve it by either completing the square or the quadratic formula and I'm just getting stuck when I reach the square root part... Help would be much appreciated!! :) Thanks!!

Answer 1

@ksaimouli I can't do that lol

Answer 2

this cubic function how to use completing the square or the quadratic formula ?????!

Answer 3

are you trying to solve this EQUATION: \(\large 125x^3 - 27=0 \) ????

Answer 4

@dpaInc Yep!

Answer 5

ok... your factorization is good...
\(\large 125x^3 - 27=0 \)
\(\large (5x-3)(25x^2+15x+9)=0 \)

solving for that first factor of (5x-3)=0 is trivial so i won't go over it.... unless you want me to... ???

but that second factor needs to be solved also: \(\large 25x^2+15x+9=0 \)
using the quadratic formula...

Answer 6

hello?

Answer 7

@dpalnc Yeah I tried the quadratic formula and I got