Algebra
posted by Bonnie on .
Please Solve:
(x+3)(x5) < 0
I got so far on this and am lost..
(x+3 <0 and x5>0) OR (x+3>0 and x5<0)
(x<3 and x > 5) OR (x> and x<5)
(x<3 and x>5) OR (3<x<5)
Do we use FOIL for this cause if we do i did this:
x^25x+3x15
x^25x+3x15
x^22x 15 >0
x^2 4x15>0
x<5, x<3
x=3 & x=5
Is any of this correct?

1. Do not use FOIL, because the problem is better solved as it is.
2. Visualize your numbers on the number line.
3. Only one of the two conditions on each side of (OR) is viable.
(x+3 <0 and x5>0) OR (x+3>0 and x5<0)
(x<3 and x > 5) OR (x> and x<5)
(x<3 and x>5) OR (3<x<5)
It is impossible to have x<3 AND x>5, so this case is eliminated. So (3<x<5) is the right answer.
This question has been answered three times before, you can go through the different answers.
http://www.jiskha.com/display.cgi?id=1247616546
http://www.jiskha.com/display.cgi?id=1247545041
http://www.jiskha.com/display.cgi?id=1247541753