4a^2-8a-21=0

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Solution for 4a^2-8a-21=0 equation:


Simplifying
4a2 + -8a + -21 = 0

Reorder the terms:
-21 + -8a + 4a2 = 0

Solving
-21 + -8a + 4a2 = 0

Solving for variable 'a'.

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

Subproblem 1

Set the factor '(-3 + -2a)' equal to zero and attempt to solve: Simplifying -3 + -2a = 0 Solving -3 + -2a = 0 Move all terms containing a to the left, all other terms to the right. Add '3' to each side of the equation. -3 + 3 + -2a = 0 + 3 Combine like terms: -3 + 3 = 0 0 + -2a = 0 + 3 -2a = 0 + 3 Combine like terms: 0 + 3 = 3 -2a = 3 Divide each side by '-2'. a = -1.5 Simplifying a = -1.5

Subproblem 2

Set the factor '(7 + -2a)' equal to zero and attempt to solve: Simplifying 7 + -2a = 0 Solving 7 + -2a = 0 Move all terms containing a to the left, all other terms to the right. Add '-7' to each side of the equation. 7 + -7 + -2a = 0 + -7 Combine like terms: 7 + -7 = 0 0 + -2a = 0 + -7 -2a = 0 + -7 Combine like terms: 0 + -7 = -7 -2a = -7 Divide each side by '-2'. a = 3.5 Simplifying a = 3.5

Solution

a = {-1.5, 3.5}

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