Any function is linear when it's slope is same
so, we will find slope by two points and then we check whether they are same
points (-3, -5) and (-1,-1):
we can use slope formula
![m=(y_2-y_1)/(x_2-x_1)](https://img.qammunity.org/2019/formulas/mathematics/middle-school/25uxp4sblay2143idvgkz738ukrk1vzo5g.png)
![m=(-1+5)/(-1+3)](https://img.qammunity.org/2019/formulas/mathematics/college/pzz8skothtoxzojd0s8r7qza6o2ah0xhoa.png)
![m=2](https://img.qammunity.org/2019/formulas/mathematics/middle-school/un10bk5gmzp7dii2g20akdti1uy538j6rs.png)
Points (-1,-1) and (0,1):
![m=(1+1)/(0+1)](https://img.qammunity.org/2019/formulas/mathematics/college/mopkw0seczj9eii4jcegdkxm9pa5ebzvoy.png)
![m=2](https://img.qammunity.org/2019/formulas/mathematics/middle-school/un10bk5gmzp7dii2g20akdti1uy538j6rs.png)
points (0,1) and (1,3):
![m=(3-1)/(1-0)](https://img.qammunity.org/2019/formulas/mathematics/college/2mde7z5vt58v3mv43wssr7ipyq9brejejz.png)
![m=2](https://img.qammunity.org/2019/formulas/mathematics/middle-school/un10bk5gmzp7dii2g20akdti1uy538j6rs.png)
points (1,3) and (3,7):
![m=(7-3)/(3-1)](https://img.qammunity.org/2019/formulas/mathematics/college/7a5jnhg25dnglap73tajsy4561eecgw9am.png)
![m=2](https://img.qammunity.org/2019/formulas/mathematics/middle-school/un10bk5gmzp7dii2g20akdti1uy538j6rs.png)
we can see that
slope is 2 for all points
so, this is linear.........................Answer