2007-12-16 20:45:56 · 3 answers · asked by Heell yeaah! 3 in Science & Mathematics ➔ Mathematics
There is a formula to find solutions of cubic functions, just as there is a formula to find solutions of quadratic functions. If you want to know it look at wiki/cubic function and at Root-finding formula, but it is cumbersome.
As far as I can see, it has only one (real) solution and it is around r = -3.6.
2007-12-16 21:33:02 · answer #1 · answered by Anonymous · 1⤊ 0⤋
r^3 - 2r^2 + 3r -6 =0
start out by transposing adding a +6 to both sides of the equation
- r^3 +2r^2 - 3r = 6
now multiply both sides of the equation by -1 to clear - from - r^2
r^2 + 2r^2 -3r = -6
now factor out r
r( r^2 +2r -3) = - 6
now factor r^2 + 2r - 3 and don't forget to use brackets around the [ (r+3)(r-1) ]
r[(r+3)(r-1)] = - 6
that's the quickest way.
2007-12-17 05:24:36 · answer #2 · answered by JUAN FRAN$$$ 7 · 0⤊ 1⤋
r^3+2r^2-3r+6=0 -multiply by -1
r(r^2+2r-3)+6=0 -grouping
r(r-1)(r+3)+6=0 -factoring (difficult sometimes)
r(r-1)(r+3)=-6 -subtract 6 from each side
Then just solve it normally
2007-12-17 05:38:56 · answer #3 · answered by Anonymous · 0⤊ 1⤋