Algebra

posted by .

please check my answers. thanxs!

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 -

    I 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

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Algebra II

    I need some help with some problems as well as need some checked. Could you please help me?
  2. Math inequalitites

    Hi, I need some help with some inequalitites. Thanks!! Use graphs to find the set. 1.(-9,0) intersection [-4,] I got [-4,0) 2. (-9,0) U [-4,10] I got (-9,10] Solve the linear inequality. Other than (empty set, use interval notation …
  3. Inequality

    please check my answers. thanxs! 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 < …
  4. college algebra

    1. find the equation of the line with the given properties. Express the equation in general form or slope-intercept form. perpendicular to the line -3x_y= -27; contains the point (9, -1) the equation of the line is ?
  5. math

    solve the polynomial inequality and graph the solution set on a real number line. express the solution set in interval notation x^3+x^2+64x+64>0 show work please
  6. math-please help,need quickly

    solve the polynomial inequality and graph the solution set on a real num ber line. express the solution set in interval notation x^3+x^2+64x+64>0 please show work
  7. Solve the polynomial inequality

    Solve the polynomial inequality and graph the solution set on a real number line. Express the solution set in interval notation. x^3+x^2+4x+4<0 The solution set is=
  8. Algebra

    Solve the polynomial inequality and graph the solution set on a real number line. Express the solution set in interval notation x^3+x^2+16x+16>0 What is the solution set?
  9. algebra

    Solve the polynomial inequality and graph the solution set on a real number line. Express the solution set in interval notation x^3+x^2+16x+16>0 What is the solution set?
  10. math/algebra

    Solve the polynomial inequality and graph the solution set on a real number line. Express the solution set in interval notation x^3+x^2+16x+16>0 What is the solution set?

More Similar Questions