Solve x^4-145x^2+144=0

$$x ^ { 4 } - 145 x ^ { 2 } + 144 = 0$$

Solve for x

$$x=-12$$

$$x=12$$

$$x=1$$

$$x=-1$$

Steps Using the Quadratic Formula

Substitute t for x^{2}.

$$t^{2}-145t+144=0$$

All equations of the form ax^{2}+bx+c=0 can be solved using the quadratic formula: \frac{-b±\sqrt{b^{2}-4ac}}{2a}. Substitute 1 for a, -145 for b, and 144 for c in the quadratic formula.

$$t=\frac{-\left(-145\right)±\sqrt{\left(-145\right)^{2}-4\times 1\times 144}}{2}$$

Do the calculations.

$$t=\frac{145±143}{2}$$

Solve the equation t=\frac{145±143}{2} when ± is plus and when ± is minus.

$$t=144 t=1$$

Since x=t^{2}, the solutions are obtained by evaluating x=±\sqrt{t} for each t.

$$x=12 x=-12 x=1 x=-1$$