##### Finite Mathematics question 18

label Mathematics
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Solve the system of linear equations using the Gauss-Jordan elimination method.

7x + 5y = 32

-3x + y = -20

Oct 20th, 2015

we need to change the equations or put them in gaus-jordan method

7   5    32

-3   1     -20                      ...........I can't draw the lines here, but i will try to make everything clear

we need to end with this type of this form

0        1      x

1         0      y

to change 7 to 1, we need to multiply the whole equation by 1/7

we end up with

1  5/7  32/7.........................in the first row

to change -3 to zero, we multiply 3 with 1 (from first row) then add top the second row

..........................more to follow, time ran out dear, but will deliver everything!

Oct 20th, 2015

the zero on the second row will be obtained after adding 3 to eliminate -3

0    22/7  -44/7

Oct 20th, 2015

So what is the answer, I am still confused? Here are the multiple choices I was given below:

A. (7, -3)

B. (6, -2)

C. (2, -6)

D. (-6, 2)

E. (-7, -2)

Oct 20th, 2015

no need to replace the second character in R2 since it's already 1

so we now change the second character on R1 (5) to zero!

-5 x 1 then add to 5 gives us zero

-5 x 32/7= -204/7

The full equation after elimination

1      0    32/7

0      1    -204/7

Oct 20th, 2015

x=32/7

y=-204/7

Oct 20th, 2015

sorry  i did other things...let me answer you asap!

Oct 20th, 2015

C. (2, -6)

Oct 20th, 2015

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Oct 20th, 2015
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Oct 20th, 2015
Aug 19th, 2017
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