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December 18, 2014

December 18, 2014

Posted by **Krissy** on Tuesday, February 5, 2013 at 11:18am.

1. Use the discriminant to determine whether the given equation has two irrational roots, two rational roots, one repeated root, or two complex roots.

x^2-4x=5

a.) Two rational roots

b.) one repreated root

c.) two complex roots

d.) two irrational roots.

2.Use the discriminant to determine whether the given equation has two irrational roots, two rational roots, one repeated root, or two complex roots.

-3x^3+19x-20=0

a.) Two rational roots

b.) one repreated root

c.) two complex roots

d.) two irrational roots.

3. Use the discriminant to determine whether the given equation has two irrational roots, two rational roots, one repeated root, or two complex roots.

-5x^2-7x-5=0

a.) Two rational roots

b.) one repreated root

c.) two complex roots

d.) two irrational roots.

4. Use the discriminant to determine whether the given equation has two irrational roots, two rational roots, one repeated root, or two complex roots

x^2-12=7x

a.) Two rational roots

b.) one repreated root

c.) two complex roots

d.) two irrational roots.

- College Algebra--Still Confused -
**Bosnian**, Tuesday, February 5, 2013 at 11:23amIn google type:

quadratic equation online

When you see list of result click on:

Free Online Quadratic Equation Solver:Solve by Quadratic Formula

When page be open in rectangle type your equation

and cilck option:

solve it!

You will see solutions step-by step and discriminant discusion.

- College Algebra--Still Confused -
**Damon**, Tuesday, February 5, 2013 at 11:27amI am only going to do one,

1. Use the discriminant to determine whether the given equation has two irrational roots, two rational roots, one repeated root, or two complex roots.

x^2-4x=5

a.) Two rational roots

b.) one repreated root

c.) two complex roots

d.) two irrational roots.

----------------

Write with a zero on the right in form

a x^2 + b x + c = 0

1 x^2 -4 x - 5 = 0

b^2 = (-4)(-4) = 16

-4ac = -4(1)(-5) = +20

so

b^2 -4ac = 16+20 = 36

sqrt (b^2 - 4ac) = +6

THAT means:

x = [ 4 +/- 6 ] /2

Two REAL Rational roots

BECAUSE

sqrt (+36) is a real number

sqrt (+36) is not sqrt( 0) which would give one repeated root

sqrt(+36) is not sqrt(-36) which would leave you with a +/- 6i which is COMPLEX number

it is not sqrt (2) or something which is not a nice rational number and can not be expressed as a ratio of whole numebers

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