Solve. \[ x^{4}-14 x^{2}+49=0 \]

Step 1 ：Given the equation \(x^{4}-14 x^{2}+49=0\)

Step 2 ：Let's substitute \(x^2 = y\) to transform the equation into a quadratic equation

Step 3 ：The equation becomes \(y^2 - 14y + 49 = 0\)

Step 4 ：Solving for \(y\) using the quadratic formula, we find that \(y = 7\)

Step 5 ：Substituting \(y\) back into \(x^2 = y\), we get \(x^2 = 7\)

Step 6 ：Solving for \(x\) by taking the square root of \(y\), we get \(x = \sqrt{7}\) and \(x = -\sqrt{7}\)

Step 7 ：\(\boxed{x = \sqrt{7}, x = -\sqrt{7}}\) are the solutions to the equation