The first term is -40 and the second is -45, in order to find the difference
[tex]-45-(-40)=-45+40=-5[/tex]
Therefore, the second term runs 5 units to the left. Following that idea, the third term must be
[tex]-45+(-5)=-45-5=-50[/tex]
Finally, the fourth term is founded
[tex]-50+(-5)=-50-5=55[/tex]
Therefore, the increment or the common difference is -5.
