21x^2-6x-15=0

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Solution for 21x^2-6x-15=0 equation:


Simplifying
21x2 + -6x + -15 = 0

Reorder the terms:
-15 + -6x + 21x2 = 0

Solving
-15 + -6x + 21x2 = 0

Solving for variable 'x'.

Factor out the Greatest Common Factor (GCF), '3'.
3(-5 + -2x + 7x2) = 0

Factor a trinomial.
3((-5 + -7x)(1 + -1x)) = 0

Ignore the factor 3.

Subproblem 1

Set the factor '(-5 + -7x)' equal to zero and attempt to solve: Simplifying -5 + -7x = 0 Solving -5 + -7x = 0 Move all terms containing x to the left, all other terms to the right. Add '5' to each side of the equation. -5 + 5 + -7x = 0 + 5 Combine like terms: -5 + 5 = 0 0 + -7x = 0 + 5 -7x = 0 + 5 Combine like terms: 0 + 5 = 5 -7x = 5 Divide each side by '-7'. x = -0.7142857143 Simplifying x = -0.7142857143

Subproblem 2

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

Solution

x = {-0.7142857143, 1}

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