30r^3+25r^2-105r=0

Solution for 30r^3+25r^2-105r=0 equation:

Simplifying
30r3 + 25r2 + -105r = 0

Reorder the terms:
-105r + 25r2 + 30r3 = 0

Solving
-105r + 25r2 + 30r3 = 0

Solving for variable 'r'.

Factor out the Greatest Common Factor (GCF), '5r'.
5r(-21 + 5r + 6r2) = 0

Factor a trinomial.
5r((-7 + -3r)(3 + -2r)) = 0

Ignore the factor 5.
Subproblem 1
Set the factor 'r' equal to zero and attempt to solve:

Simplifying
r = 0

Solving
r = 0

Move all terms containing r to the left, all other terms to the right.

Simplifying
r = 0
Subproblem 2
Set the factor '(-7 + -3r)' equal to zero and attempt to solve:

Simplifying
-7 + -3r = 0

Solving
-7 + -3r = 0

Move all terms containing r to the left, all other terms to the right.

Add '7' to each side of the equation.
-7 + 7 + -3r = 0 + 7

Combine like terms: -7 + 7 = 0
0 + -3r = 0 + 7
-3r = 0 + 7

Combine like terms: 0 + 7 = 7
-3r = 7

Divide each side by '-3'.
r = -2.333333333

Simplifying
r = -2.333333333
Subproblem 3
Set the factor '(3 + -2r)' equal to zero and attempt to solve:

Simplifying
3 + -2r = 0

Solving
3 + -2r = 0

Move all terms containing r to the left, all other terms to the right.

Add '-3' to each side of the equation.
3 + -3 + -2r = 0 + -3

Combine like terms: 3 + -3 = 0
0 + -2r = 0 + -3
-2r = 0 + -3

Combine like terms: 0 + -3 = -3
-2r = -3

Divide each side by '-2'.
r = 1.5

Simplifying
r = 1.5
Solution
r = {0, -2.333333333, 1.5}