How do you solve the system using the elimination method for 4x-y=9 and x-3y=16?

1 Answer
Jul 7, 2015

Answer:

#(x,y) = (1,-5)#

Explanation:

[1]#color(white)("XXXX")##4x-y=9#
[2]#color(white)("XXXX")##x-3y = 16#

Multiply [2] by 4 to obtain the same coefficient of #x# as in [1]
[3]#color(white)("XXXX")##4x-12y = 64#

Subtract [1] from [3]
[4]#color(white)("XXXX")##-11y = 55#

Solve for #y#
[5]#color(white)("XXXX")##y= -5#

Substitute #y=-5# back into [1]
[6]#color(white)("XXXX")##4x - (-5) = 9#

Solve for #x#
[7]#color(white)("XXXX")##4x = 4#

[8]#color(white)("XXXX")##x = 1#