(x*x)-(k*k)=0

Solution for (x*x)-(k*k)=0 equation:

Simplifying
(x * x) + -1(k * k) = 0

Multiply x * x
(x2) + -1(k * k) = 0
x2 + -1(k * k) = 0

Multiply k * k
x2 + -1(k2) = 0

Reorder the terms:
-1k2 + x2 = 0

Solving
-1k2 + x2 = 0

Solving for variable 'k'.

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

Add '-1x2' to each side of the equation.
-1k2 + x2 + -1x2 = 0 + -1x2

Combine like terms: x2 + -1x2 = 0
-1k2 + 0 = 0 + -1x2
-1k2 = 0 + -1x2
Remove the zero:
-1k2 = -1x2

Divide each side by '-1'.
k2 = x2

Simplifying
k2 = x2

Take the square root of each side:
k = {-1x, x}