3r^3+21r^2=90r

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Solution for 3r^3+21r^2=90r equation:


Simplifying
3r3 + 21r2 = 90r

Reorder the terms:
21r2 + 3r3 = 90r

Solving
21r2 + 3r3 = 90r

Solving for variable 'r'.

Reorder the terms:
-90r + 21r2 + 3r3 = 90r + -90r

Combine like terms: 90r + -90r = 0
-90r + 21r2 + 3r3 = 0

Factor out the Greatest Common Factor (GCF), '3r'.
3r(-30 + 7r + r2) = 0

Factor a trinomial.
3r((-10 + -1r)(3 + -1r)) = 0

Ignore the factor 3.

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 '(-10 + -1r)' equal to zero and attempt to solve: Simplifying -10 + -1r = 0 Solving -10 + -1r = 0 Move all terms containing r to the left, all other terms to the right. Add '10' to each side of the equation. -10 + 10 + -1r = 0 + 10 Combine like terms: -10 + 10 = 0 0 + -1r = 0 + 10 -1r = 0 + 10 Combine like terms: 0 + 10 = 10 -1r = 10 Divide each side by '-1'. r = -10 Simplifying r = -10

Subproblem 3

Set the factor '(3 + -1r)' equal to zero and attempt to solve: Simplifying 3 + -1r = 0 Solving 3 + -1r = 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 + -1r = 0 + -3 Combine like terms: 3 + -3 = 0 0 + -1r = 0 + -3 -1r = 0 + -3 Combine like terms: 0 + -3 = -3 -1r = -3 Divide each side by '-1'. r = 3 Simplifying r = 3

Solution

r = {0, -10, 3}

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