21r^2+8r-4=

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Solution for 21r^2+8r-4= equation:


Simplifying
21r2 + 8r + -4 = 0

Reorder the terms:
-4 + 8r + 21r2 = 0

Solving
-4 + 8r + 21r2 = 0

Solving for variable 'r'.

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

Subproblem 1

Set the factor '(-2 + -3r)' equal to zero and attempt to solve: Simplifying -2 + -3r = 0 Solving -2 + -3r = 0 Move all terms containing r to the left, all other terms to the right. Add '2' to each side of the equation. -2 + 2 + -3r = 0 + 2 Combine like terms: -2 + 2 = 0 0 + -3r = 0 + 2 -3r = 0 + 2 Combine like terms: 0 + 2 = 2 -3r = 2 Divide each side by '-3'. r = -0.6666666667 Simplifying r = -0.6666666667

Subproblem 2

Set the factor '(2 + -7r)' equal to zero and attempt to solve: Simplifying 2 + -7r = 0 Solving 2 + -7r = 0 Move all terms containing r to the left, all other terms to the right. Add '-2' to each side of the equation. 2 + -2 + -7r = 0 + -2 Combine like terms: 2 + -2 = 0 0 + -7r = 0 + -2 -7r = 0 + -2 Combine like terms: 0 + -2 = -2 -7r = -2 Divide each side by '-7'. r = 0.2857142857 Simplifying r = 0.2857142857

Solution

r = {-0.6666666667, 0.2857142857}

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