(x*x+16)=0

To solve the equation \( x^2 + 16 = 0 \), follow these steps:

1. Subtract 16 from both sides: \[ x^2 = -16 \]

2. Take the square root of both sides. Remember that the square root of a negative number involves imaginary numbers: \[ x = \pm \sqrt{-16} \] This can be simplified to: \[ x = \pm 4i \]

So, the solutions to the equation \( x^2 + 16 = 0 \) are: \[ x = 4i \quad \text{and} \quad x = -4i \]