How do you solve sqrt(3x-8) = 23x8=2 and find any extraneous solutions?

1 Answer
May 29, 2016

x = 4x=4

Explanation:

As we have sqrt(3x-8)3x8 in the equation, we will require that 3x-8 >= 03x80, that is, x >= 8/3x83.

sqrt(3x-8) = 23x8=2

=>(sqrt(3x-8))^2 = 2^2(3x8)2=22

=> 3x-8 = 43x8=4

(Note that typically (sqrt(a))^2 = sqrt(a^2) = |a|(a)2=a2=|a|, but we already required 3x-8>=03x80, meaning |3x-8| = 3x-8|3x8|=3x8)

=> 3x = 123x=12

:. x = 4

Checking our answer, we find that

sqrt(3(4)-8) = sqrt(4) = 2

as desired.