-x^2+6.5+3.5=0

Solution for -x^2+6.5+3.5=0 equation:

Simplifying
-1x2 + 6.5 + 3.5 = 0

Reorder the terms:
6.5 + 3.5 + -1x2 = 0

Combine like terms: 6.5 + 3.5 = 10
10 + -1x2 = 0

Solving
10 + -1x2 = 0

Solving for variable 'x'.

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

Add '-10' to each side of the equation.
10 + -10 + -1x2 = 0 + -10

Combine like terms: 10 + -10 = 0
0 + -1x2 = 0 + -10
-1x2 = 0 + -10

Combine like terms: 0 + -10 = -10
-1x2 = -10

Divide each side by '-1'.
x2 = 10

Simplifying
x2 = 10

Take the square root of each side:
x = {-3.16227766, 3.16227766}