Thursday

April 2, 2015

April 2, 2015

Posted by **Liz** on Wednesday, October 24, 2007 at 10:02pm.

Solve the polynomial inequality and graph the solution set on a number line. Express the solution set in interval notation.

x^2 - 6x + 5 > 0

-I got (-ininity,1) u (5, infinity)

x^2 - 3x - 18 < 0

-I got (-infinity,-3) u (6, infinity)

x^2 - 3x - 28 ¡Ü 0

-I got (-ininity,-4] u [7,infinity)

- Algebra -
**Reiny**, Wednesday, October 24, 2007 at 10:58pmI don't understand the notation in your answer, this is how I would do this question. I will do the first one.

x^2 - 6x + 5 > 0

(x-1)(x-5) > 0

giving me "separators" at x=1 and x=5

So we have 3 regions on the number line

a)all values x<1

b) all values between 1 and 5

c) all values x>5

I then take an arbitrary value in each of these regions and test if the result is positive, not really caring about the actual answer but only its sign.

a) eg. let x=0 we get (-)(-) which is positive, so x<1 works

b) let x = 4, we get (+)(-) which is negative, so that region does not work

c) x=10 we get (+)(+) which is positive so x>5 works

therefore x<1 OR x>5 is the solution

**Answer this Question**

**Related Questions**

Inequality - please check my answers. thanxs! Solve the polynomial inequality ...

Solve the polynomial inequality - Solve the polynomial inequality and graph the ...

math - solve the polynomial inequality and graph the solution set on a real ...

Algebra II - I need some help with some problems as well as need some checked. ...

college algebra - 1. find the equation of the line with the given properties. ...

math-please help,need quickly - solve the polynomial inequality and graph the ...

Math inequalitites - Hi, I need some help with some inequalitites. Thanks!! Use ...

Algebra - Can you please check my answers? Solve the rational inequality and ...

algebra - solve the inequality. Express the solution using interval notation and...

math - solve the polynomial inequality and graph the solution set on a real ...