How do you graph #x+y<-4#?

1 Answer
Tony B
Mar 18, 2017

See explanation

Note: if the inequality had been #x+y<=-4# you would have used a solid line.

Explanation:

Although not the case, just for now consider it as #x+y=-4# to determine the line to be graphed.

Subtract #x# from both sides

#y=-x-4#

This will plot the line. However what we really have is:

#x+y<-44#

Subtract #x# from both sides

#y<-x-4#

As #y# is 'less than' something done to #x#, the value of #y# can never actually be the value on the line. Consequently we use a dotted line to signify this condition. You would also use a dotted line for greater than.

To indicate that #y# can take on any value less then the line the area under the line (less than) is shaded.

So we have:
Tony B

Related questions
See all questions in Inequalities with Addition and Subtraction
Impact of this question
1324 views around the world
You can reuse this answer
Creative Commons License