How do you solve using gaussian elimination or gauss-jordan elimination, 2x + 3y = -22x+3y=2, -6x + y = -146x+y=14?

1 Answer
Jun 11, 2017

color(brown)(((1,0,|,+2),(0,1,|,-2)))

x=2 and y=-2

Explanation:

Using the form:

(x,y,|,"answer")

color(brown)(((2,3,|,-2),(-6,+1,|,-14)))
" "(-3)xxRow_1
" "darr

color(brown)(((-6,-9,|,+6),(-6,+1,|,-14)))
" "Row_1-Row_2
" "darr

color(brown)(((0,-10,|,+20),(-6,+1,|,-14)))
" "Row_1-:(-10)
" "darr

color(brown)(((0,+1,|,-2),(-6,+1,|,-14)))
" "Row_2-Row_1
" "darr

color(brown)(((0,+1,|,-2),(-6,0,|,-12)))
" "Row_2-:(-6)
" "darr

color(brown)(((0,+1,|,-2),(+1,0,|,+2)))

Write in row echelon form

color(brown)(((1,0,|,+2),(0,1,|,-2)))
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Check that x=2 and y=-2

2x+3y=-2" "->" "LHS->2(2)+3(-2)=4-6=-2

-6x+y=-14" "->" "LHS->-6(2)+(-2)=-14