Answer:
[tex]T_{23}=-153[/tex]
Step-by-step explanation:
[tex]T_{23}=a+(n-1)d\\[/tex]
[tex]=a+(23-1)d=a+22d[/tex]
Now [tex]a=-21[/tex] and
[tex]d=-27-(-21)\\=-6[/tex]
So [tex]T_{23}==21+((22)6\times-1)[/tex]
[tex]=-153[/tex]
