Rational Exponents: Simplifying

[shawie]

I'm not really sure how to approach this problem:

(4-x)^1/2=8

 

[tkhunny]

(4-x)^1/2=8
Think about the Domain: 4-x ≥ 0 or x ≤ 4
Then, 4-x = 64
Can you go from there?

 

[Denis]

I'm not really sure how to approach this problem:
(4-x)^1/2=8

If you're not familiar with Domain, just square both sides:
(4-x)^1/2 squared = 4-x
8 squared = 64; so 4-x = 64.

Remember that sqrt(n) squared = n.
sqrt(25) = 5, right? 5 squared = 25, right?

Wonder if "domain" means: get rid of mother :roll:

 

[shawie]

thank you both for the help

(4-x)^1/2=8
Think about the Domain: 4-x ≥ 0 or x ≤ 4
Then, 4-x = 64
Can you go from there?

...i think so, i just have to solve for x right?

 

[Gene]

Yes, but be sure to try the answer in the ORIGINAL equation to make sure it works. When you do the squaring you introduce some answers that won't work.