How do you solve #3x^2 = 108#?

Question

12002 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2017-07-07T19:41:42

#x=+-6#

#3x^2 = 108#

#(cancel(3)x^2)/cancel(3) = 108/3#

#x^2 = 36#

#x=sqrt(36)#

#x=+-6#

Answer 2 · 2017-07-07T19:56:07

#x = pm 6#

We have: #3 x^(2) = 108#

First, let's divide both sides of the equation by #3#:

#Rightarrow frac(3 x^(2))(3) = frac(108)(3)#

#Rightarrow x^(2) = 36#

Then, let's subtract #36# from both sides:

#Rightarrow x^(2) - 36 = 36 - 36#

#Rightarrow x^(2) - 36 = 0#

The left-hand side of the equation is now in the form of a difference of squares.

We can factorise it in the following way:

#Rightarrow (x + 6)(x - 6) = 0#

Using the null factor law:

#therefore x = pm 6#

Therefore, the solutions to the equation are #x =- 6# and #x = 6#.