How do you solve x^2 = 121?

Question

I'm confused on how to get this.
Can someone help me solve #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 #+-# signs. Or you can write in standard form and factor.

Given #x^2 = 121#

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

#x = +-11#

This separates into:

#x = 11# and #x = -11#

Another way to do it is:

Given #x^2 = 121#

Write in standard form by subtracting 121 from both sides:

#x^2-121=0#

The form #x^2-c# always factors into #(x+sqrtc)(x-sqrtc)#:

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

Set both factors equal to 0:

#x +11=0# and #x-11=0#

#x = -11# and #x = 11 larr# same answer