How do you solve x^2 = 121?

Question

I'm confused on how to get this.
Can someone help me solve $x^{2}$ $x^2$ = 121?

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Answer 1 · 2018-06-05T15:41:26

You take the square root of both sides and make the right side have $\pm$ $+-$ signs. Or you can write in standard form and factor.

Given $x^{2} = 121$ $x^2 = 121$

Take the square root of both sides (don't forget the $\pm$ $+-$ on the right):

$x = \pm 11$ $x = +-11$

This separates into:

$x = 11$ $x = 11$ and $x = - 11$ $x = -11$

Another way to do it is:

Given $x^{2} = 121$ $x^2 = 121$

Write in standard form by subtracting 121 from both sides:

$x^{2} - 121 = 0$ $x^2-121=0$

The form $x^{2} - c$ $x^2-c$ always factors into $(x + \sqrt{c}) (x - \sqrt{c})$ $(x+sqrtc)(x-sqrtc)$ :

$(x + 11) (x - 11) = 0$ $(x+11)(x-11) = 0$

Set both factors equal to 0:

$x + 11 = 0$ $x +11=0$ and $x - 11 = 0$ $x-11=0$

$x = - 11$ $x = -11$ and $x = 11 \leftarrow$ $x = 11 larr$ same answer