Well, we do not see the lines clearly (if they are dotted (inequality) or solid (inequality or equal) ), but we'll come back to this.
y<x+1  can be simplified to be y<x if we ignore the constants, so the valid part is BELOW the line, since (y<)
x-4y <=4
again, ignore the constants and simplify to 
x-y<0 or
y>x   so the valid part is ABOVE the line (since y>)
There are two graphs that satisfy BOTH conditions, pink (slope=1) at the bottom, and blue (slope = 1/4) on top, i.e. first and third graph.
For the absolute inequality (y<x+1), the red line must be dotted.
For the <= condition, the blue line must be solid.
As we cannot see the lines clearly, you will make the choice between the first and third graphs according to the previous paragraph.
        
                    
             
        
        
        
Volume of a ball = (4/3)πr³
When r = 18cm, V = (4/3)×3.14×18³ =24416.64 cm³
When r = 12cm, V = (4/3)×3.14×12³ =7234.56 cm³ 
 Difference = 24416.64 - 7234.56 = 17182.08 cm³
the volume of air in the larger ball is <span>17182.08 cm³ greater than smaller ball </span>
        
                    
             
        
        
        
Answer:
The vertices are (-16,-5) and (14,-5)
The foci are (-26,-5) and (24,-5)
Please, see the attached file.
Thanks.
 
        
                    
             
        
        
        
if the diameter of a circle is 15, its radius is half that or 7.5.
![\bf \textit{area of a circle}\\\\ A=\pi r^2~~ \begin{cases} r=radius\\[-0.5em] \hrulefill\\ r=7.5 \end{cases} A=\pi (7.5)^2\implies A=56.25\pi \implies \stackrel{\pi =3.14}{A=176.625}](https://tex.z-dn.net/?f=%5Cbf%20%5Ctextit%7Barea%20of%20a%20circle%7D%5C%5C%5C%5C%20A%3D%5Cpi%20r%5E2~~%20%5Cbegin%7Bcases%7D%20r%3Dradius%5C%5C%5B-0.5em%5D%20%5Chrulefill%5C%5C%20r%3D7.5%20%5Cend%7Bcases%7D%20A%3D%5Cpi%20%287.5%29%5E2%5Cimplies%20A%3D56.25%5Cpi%20%5Cimplies%20%5Cstackrel%7B%5Cpi%20%3D3.14%7D%7BA%3D176.625%7D%20)