Posted by **rebekah** on Monday, October 1, 2012 at 9:53pm.

#1. solve x^2-1<0 I got (-1,1)

#2 x(x+1) >20

I got (-infinity, -4) U (5,infinity)

#3

what is the domain of this function? f(x)= squre root of (x-3x^2)

i got [-1/3,0]

thanks!!!

- check my precalc -
**Reiny**, Monday, October 1, 2012 at 10:06pm
#1

correct

for #2

x^2 + x - 20 > 0

(x+5)(x-4) > 0

critical values are -5 and +4

In my notation it would be

x < -5 OR x > 4

Your (-infinity, -4) U (5,infinity) should then be

**(-infinity, -5) U (4,infinity) **

#3

correct

- check my precalc -
**rebekah**, Tuesday, October 2, 2012 at 6:55am
Thanks so much!

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