Add abs( K ) to both sides so we can start isolating x on the left:

\qquad (x - H)^2 = -K

Take the square root of both sides to get rid of the exponent.

\qquad \sqrt{(x - H)^2} = \pm \sqrt{-K}

Be sure to consider both positive and negative CONSTANT, since squaring either one results in -K.

\qquad x - H = \pm CONSTANT

Add abs( H ) to both sides to isolate x on the left: Subtract abs( H ) from both sides to isolate x on the left:

\qquad x = H \pm CONSTANT

Add and subtract CONSTANT to find the two possible solutions:

\qquad x = H + CONSTANT \quad \text{OR_TEXT} \quad x = H - CONSTANT

The function intersects the x-axis where f(x) = 0, so solve the equation:

\qquad (x - H)^2 + K = 0