ANSWER 
  or
 or 
EXPLANATION
For 
We make y the subject to obtain,
 
We can easily graph this function, because we just have to transform the graph of  by shifting the intercept up to
 by shifting the intercept up to  .
.
As for the straight line,  ,
,
We find the intercepts as follows,
When  .
.
When  .
.
We plot the points  and
 and
  .
.
We now draw the two graphs on the same graph sheet. The intersection of the two graphs gives the solution to be
  or
 or 
See graph