questions on attachment!

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- July 23rd 2006, 06:28 PMLaneHelp ME Please!!!
questions on attachment!

- July 23rd 2006, 09:30 PMearbothproblem nr. 4 onlyQuote:

Originally Posted by**Lane**

use Cramer's rule:

. So it's answer C.

Greetings

EB - July 23rd 2006, 09:35 PMearbothproblem nr. 5 onlyQuote:

Originally Posted by**Lane**

it's me again.

Use the same method as in prob. nr. 4.:

. Solving this quadratic equation you should get x= 3 or x = 10.

Greetings

EB - July 23rd 2006, 09:52 PMearbothproblem nr. 2 onlyQuote:

Originally Posted by**Lane**

(I assume that there is a typo in the first row)

Calculate: R2-2*R1 and R3-R1. You'll get:

Now calculate R3+4*R2:

So you get z = -1. Now re-substitute this value into equation 2 and afterward plug in the values for y and z into the first equation. You should get: [4, -5, -1]

Greetings

EB - July 23rd 2006, 10:56 PMCaptainBlackProblem #3 only
The augmented matrix is equivalent to the system of equations:

Now check the candidate solutions to see which satisfy these equations.

The first equation is satisfied by those candidate solutions with , and the second by those candidates with , so it looks like (C) is the required answer.

RonL - July 23rd 2006, 11:07 PMCaptainBlackProblem #1 only
Let:

A: Swap rows 1 and 2 gives:

B: Replace row 2 by row 2 plus -3 times row 1

I am sure you can now do part C yourself.

RonL