Question #393ba

1 Answer
Jun 10, 2017

Use #y"-intercept"# and #x"-intercept"# or any two points on the line.

Explanation:

Looking at the equation, it is apparent that it would follow a linear model as there are no exponents or powers (eg #x^2#)

Then what we can do if find to points on the graph and draw a line through these points. The easiest points to find are usually the #y"-intercept"# and #x"-intercept"#

The #y"-intercept"# is when #x=0#, so to find that point, make #x=0# in the equation, and solve for #y#

#x=0#

#=>-2(0)+y=2#

#=>y=2#

Hence, when #x=0#, #y=2#. This represents the point #(0,2)#. So we should plot this point:

Geogebra.com

Then we calculate the other point, the #x"-intercept"#

The #x"-intercept"# is when #y=0#, so to find that point, make #y=0# in the equation, and solve for #x#

#y=0#

#=>-2x+(0)=2#

#=>-2x=2#

#=>x=2/-2#

#=>x=-1#

Hence, when #y=0#, #x=-1#. This represents the point #(-1,0)#. So we should plot this point with the other point:

Geogebra.com

Now join the two points with a straight line:

Geogebra.com

And you have the graph of your equation

You can use any two poinst on the line though. The only difference is that instead of finding when #x=0# or #y=0#, you would find when #x="another number like "3# or when #y="another number like "4#

It is easier to find the #y"-intercept"# and #x"-intercept"# but if you want to challenge yourself, find two points other than the #y"-intercept"# and #x"-intercept"#