Mammoth Memory

Inequalities and graphs example 3

 

Solve the inequality

6x-y>-2 

Subtract 6x from both sides to get y on its own.

6x-6x-y>-2-6x

-y>-2-6x 

Divide both sides by -1  to get a positive. Don’t forget to FLIP the sign.

-y-1<-2x-1-6x-1

y<2+6x 

or y<6x+2 

First let's calculate points on the graph

x=-2       then   y<6(-2)+2=-12+2=-10

x=-1       then   y<6(-1)+2=-6+2=-4     

x=0             then   y<6(0)+2=0+2=2      

x=1             then   y<6×1+2=6+2=8         

x=2             then   y<6×2+2=12+2=14     

Now draw a graph and mark on the above points. Don’t forget to use a DOTTED line.

Draw the line make sure its dotted

Now pick a point NOT on the line

Find a position not on the line

Choose   x=0   y=0

y<6x+2 

0<6(0)+2 

0<2  

This reads zero is less than two.

This does satisfy the inequality, SHADE IT.

Shade it if its satisfied