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Simplifying
4x2 + -84 = 0
Reorder the terms:
-84 + 4x2 = 0
Solving
-84 + 4x2 = 0
Solving for variable 'x'.
Move all terms containing x to the left, all other terms to the right.
Add '84' to each side of the equation.
-84 + 84 + 4x2 = 0 + 84
Combine like terms: -84 + 84 = 0
0 + 4x2 = 0 + 84
4x2 = 0 + 84
Combine like terms: 0 + 84 = 84
4x2 = 84
Divide each side by '4'.
x2 = 21
Simplifying
x2 = 21
Take the square root of each side:
x = {-4.582575695, 4.582575695}
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