EXPLANATION
Given the sequence where a_11=-3 and d=2
This is an arithmetic sequence with the following equation:
[tex]a_n=a_1+(n-1)d[/tex]Replacing terms:
[tex]-3=a_1+(11-1)\cdot2[/tex]Removing the parentheses:
[tex]-3=a_1+10\cdot2[/tex]Multiplying numbers:
[tex]-3=a_1+20[/tex]Subtracting -20 to both sides:
[tex]-3-20=a_1[/tex][tex]-23=a_1[/tex]The answer is a_1=-23
