# How do you solve 2x^4 - 10x^2 = 0?

Oct 31, 2015

$x = + \sqrt{5}$
$x = - \sqrt{5}$

#### Explanation:

Here,

It is easy to solve for quadratic function but difficult if the power rises up to more than 3,

in this case you let ${x}^{2} = a$
Now replace the value of ${x}^{2}$ with $a$

The new equation is,

$2 {a}^{2} - 10 a$ =0

Take 2 common for both the terms,

2 ( ${a}^{2} - 5 a$) =0

${a}^{2} - 5 a = 0$

${a}^{2} = 5 a$

Cancel one a ,

SO,

$a = 5$

Now replace this value of a in ${x}^{2}$

SO,

${x}^{2}$ = 5
$x = \pm \sqrt{5}$

So, either, $x = + \sqrt{5}$
or, $x = - \sqrt{5}$