Question

How do I use gauss-jordan to solve this? Can you explain the steps and show what you multiplied, added, subtracted, etc to each row?

8x + 2y = -68
-7x - y = 55

Answer 1

augmented matrix
+8 +2 -68
-7 -1 +55
you have two rows, three columns
now go to
http://www.gregthatcher.com/Mathematics/GaussJordan.aspx

Answer 2

-7
-6

Answer 3

divide first row by 8 to get 1 in upper left
1 1/4 -17/2

add 7 times new first row to second to get 0 below the one
1 +1/4 -17/2
0 +3/4 -9/2

subtract 1/3 times row 2 from row 1 to get rid of that 1/4 in row 1
1 0 -7
0 3/4 -9/2

multiply second row by 4/3 to get 1 in 2,2 spot
1 0 -7
0 1 -6
done
1 x + 0 y = -7
0 x + 1 y = -6