2(x*x)+13-84=0

Solution for 2(x*x)+13-84=0 equation:

Simplifying
2(x * x) + 13 + -84 = 0

Multiply x * x
2(x2) + 13 + -84 = 0

Reorder the terms:
13 + -84 + 2x2 = 0

Combine like terms: 13 + -84 = -71
-71 + 2x2 = 0

Solving
-71 + 2x2 = 0

Solving for variable 'x'.

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

Add '71' to each side of the equation.
-71 + 71 + 2x2 = 0 + 71

Combine like terms: -71 + 71 = 0
0 + 2x2 = 0 + 71
2x2 = 0 + 71

Combine like terms: 0 + 71 = 71
2x2 = 71

Divide each side by '2'.
x2 = 35.5

Simplifying
x2 = 35.5

Take the square root of each side:
x = {-5.958187644, 5.958187644}