3x^2-9=81

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Solution for 3x^2-9=81 equation:


Simplifying
3x2 + -9 = 81

Reorder the terms:
-9 + 3x2 = 81

Solving
-9 + 3x2 = 81

Solving for variable 'x'.

Move all terms containing x to the left, all other terms to the right.

Add '9' to each side of the equation.
-9 + 9 + 3x2 = 81 + 9

Combine like terms: -9 + 9 = 0
0 + 3x2 = 81 + 9
3x2 = 81 + 9

Combine like terms: 81 + 9 = 90
3x2 = 90

Divide each side by '3'.
x2 = 30

Simplifying
x2 = 30

Take the square root of each side:
x = {-5.477225575, 5.477225575}

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