Science

Math

Humanities

... and beyond

Socratic Meta
Featured Answers

Topics

How do you solve the following linear system #4x - y = 5 , 4x + 4y = -4 #?

1 Answer

Nov 17, 2015

#(x,y) = (4/5,-9/5)#

Explanation:

Given
[1]#color(white)("XXX")4x-y=5#
[2]#color(white)("XXX")4x+4y=-4#

Subtract [2] from [1]
[3]#color(white)("XXX")-5y= 9#

Divide [3] by #(-5)#
[4]#color(white)("XXX")y= -9/5#

Divide [2] by #4#
[5]#color(white)("XXX")x+y=-1#

Substitute #(-9/5)# from [4] for #y# in [5]
[6]#color(white)("XXX")x-9/5= -1#

Add #9/5# to both sides of [6]
[7]#color(white)("XXX")x=4/5#

Related questions

See all questions in Systems Using Substitution

Impact of this question

1076 views around the world

You can reuse this answer
Creative Commons License