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Simplifying
4a2 + -81 = 0
Reorder the terms:
-81 + 4a2 = 0
Solving
-81 + 4a2 = 0
Solving for variable 'a'.
Move all terms containing a to the left, all other terms to the right.
Add '81' to each side of the equation.
-81 + 81 + 4a2 = 0 + 81
Combine like terms: -81 + 81 = 0
0 + 4a2 = 0 + 81
4a2 = 0 + 81
Combine like terms: 0 + 81 = 81
4a2 = 81
Divide each side by '4'.
a2 = 20.25
Simplifying
a2 = 20.25
Take the square root of each side:
a = {-4.5, 4.5}
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