Question

Solve : x4 - 13x² +42 = 0​

Answer 1

Step-by-step explanation:

take x^4 as t and then solve the quadratic in t

Answer 2

Step-by-step explanation:

Given: $x^{4} - 13x^{2} +42 = 0$

To find: Solution of the above equation.

For calculation of the equation,

Let us substitute $x^{2} = t$

∴ $x^{4} - 13x^{2} +42 = 0$ ,

⇒ $t^{2} - 13t-42=0$

We know that $42=7$ × $6$

Thus,

⇒ $(t-7) (t-6) = 0$

⇒ $t=(7), (6)$

⇒$x^{2} = 7,6$

⇒ $x=I\sqrt{7} , I\sqrt{6}$

Hence, the value of $x=I\sqrt{7} , I\sqrt{6}$.