10r^2+21r+8=0

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Solution for 10r^2+21r+8=0 equation:


Simplifying
10r2 + 21r + 8 = 0

Reorder the terms:
8 + 21r + 10r2 = 0

Solving
8 + 21r + 10r2 = 0

Solving for variable 'r'.

Factor a trinomial.
(8 + 5r)(1 + 2r) = 0

Subproblem 1

Set the factor '(8 + 5r)' equal to zero and attempt to solve: Simplifying 8 + 5r = 0 Solving 8 + 5r = 0 Move all terms containing r to the left, all other terms to the right. Add '-8' to each side of the equation. 8 + -8 + 5r = 0 + -8 Combine like terms: 8 + -8 = 0 0 + 5r = 0 + -8 5r = 0 + -8 Combine like terms: 0 + -8 = -8 5r = -8 Divide each side by '5'. r = -1.6 Simplifying r = -1.6

Subproblem 2

Set the factor '(1 + 2r)' equal to zero and attempt to solve: Simplifying 1 + 2r = 0 Solving 1 + 2r = 0 Move all terms containing r to the left, all other terms to the right. Add '-1' to each side of the equation. 1 + -1 + 2r = 0 + -1 Combine like terms: 1 + -1 = 0 0 + 2r = 0 + -1 2r = 0 + -1 Combine like terms: 0 + -1 = -1 2r = -1 Divide each side by '2'. r = -0.5 Simplifying r = -0.5

Solution

r = {-1.6, -0.5}

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