How do you graph the line #x-y=2#?

1 Answer
Tony B
Apr 6, 2016

See explanation

Explanation:

Given:#" " color(brown)(x-y=2)#

#color(green)("Step 1: Rearrange the equation into standard form")#

Add #color(blue)(y)# to both sides

#color(brown)(x-ycolor(blue)(+y)=2color(blue)(+y))#

#=> x+0=2+y#

Subtract #color(blue)(2)# from both sides

#=>color(brown)(x color(blue)(-2)=2color(blue)(-2)+y)#

#=>x-2=0+y#

#color(green)(y=x-2)#

'~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

#color(green)("Step 2: Build data so that graph can be plotted")#
Selecting values for #x# at random

Let #x=-1" then "y=-1-2 = -3#

Let #x=0" then "y=0-2=-2#

Let #x=2" then "y=2-2=0#

We now have three sets of point

Point #P_1->(x,y)->(-1,-3)#
Point #P_2->(x,y)->(0,-2)#
Point #P_2->(x,y)->(2,0)#

Mark these point on graph paper and draw a line through them extending it to the edges of the scales. If all three dots must line up. If not then there is an error some where. 3 dots are better than just 2 as they form a check.

Your graph should look something like this:
Tony B

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