1.- a1= -27 d= 2 12 terminos
-27,-25,-23,-21,-19,-17,-15,-13,-11,-9,-7,-5
2.- a1= -34/9 d= 2/3 9 terminos
-34/9-2/3=72-18/18=54/18-2/3=162-36/54=126/54-2/3=378-108/162=270/162-2/3=810-324/486=486/486-2/3=1458-972/1458

3.- a1= 67 d= -3.75 10 terminos
67-63.25,-59.5,-55.75,-52,-48.25,-44.5,-40.75,-37,-33.25
4.- a1= 128.15 d=-12.35 7 terminos
128.15,-115.8,-103.45,-91.1,-78.75,-66.4,-54.05
5.- a1= 63/7 d= -9/7 11 terminos
63/7-9/7=54/7=45/7=36/7=27/7=18/7=9/7=0=-9/7=-18/7
6.- a1= -3 an= 187 n= -75
(-3+187/2)=(190(-75)/2=7125
7.- a1= 2 an= 215 n= 164
(2+215)/2=(217(164)/2=17794
8.- a1= 21 an= 276 n= 321
(21+276)/2=(278(321)/2=44619
9.- a1= -78 d= -49
-78,-29,-20-69,-118,-167,-216,-265,-314
10.- a1= 345 d= -169
 345,-176,-7,-162,-331,-500,-669,-838