40r^2-285r-280=0

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Solution for 40r^2-285r-280=0 equation:


Simplifying
40r2 + -285r + -280 = 0

Reorder the terms:
-280 + -285r + 40r2 = 0

Solving
-280 + -285r + 40r2 = 0

Solving for variable 'r'.

Factor out the Greatest Common Factor (GCF), '5'.
5(-56 + -57r + 8r2) = 0

Factor a trinomial.
5((-7 + -8r)(8 + -1r)) = 0

Ignore the factor 5.

Subproblem 1

Set the factor '(-7 + -8r)' equal to zero and attempt to solve: Simplifying -7 + -8r = 0 Solving -7 + -8r = 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 + -8r = 0 + 7 Combine like terms: -7 + 7 = 0 0 + -8r = 0 + 7 -8r = 0 + 7 Combine like terms: 0 + 7 = 7 -8r = 7 Divide each side by '-8'. r = -0.875 Simplifying r = -0.875

Subproblem 2

Set the factor '(8 + -1r)' equal to zero and attempt to solve: Simplifying 8 + -1r = 0 Solving 8 + -1r = 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 + -1r = 0 + -8 Combine like terms: 8 + -8 = 0 0 + -1r = 0 + -8 -1r = 0 + -8 Combine like terms: 0 + -8 = -8 -1r = -8 Divide each side by '-1'. r = 8 Simplifying r = 8

Solution

r = {-0.875, 8}

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