1.- a1= -27 d= 2 12 terminos

N=a1 + d = - 27+2=-25+2=-23+2=-21+2=-19+2=-17+2=-15+2=-13+2=-11+2=-9+2=-7+2=-5+2=5-3+2=-1




2.- a1= -34/9 d= 2/3 9 terminos

n=a1+d=


34/9+2/3=120/27+2/3=414/81=1404/243=4711/729+2/3=15591/2187+2/3=51147/6561+2/3=166563/19683+2/3=539055/59049+2/3=1735263/177147


3.- a1= 67 d= -3.75 10 terminos

n=a1+d=


34/9+2/3=120/27+2/3=414/81=1404/243=4711/729+2/3=15591/2187+2/3=51147/6561+2/3=166563/19683+2/3=539055/59049+2/3=1735263/177147


4.- a1= 128.15 d=-12.35 7 terminos

n=a1+d=


128.15+12.35=140.50+12.35=152.85+12.35=165.20+12.35=177.55+12.35=189.90+12.35=202.25+12.35=214.60+12.35=226.95




5.- a1= 63/7 d= -9/7 11 terminos


N=a1+d= 63/7+9/7=72/7+9/7=81/7+9/7=90/7+9/7=99/7+9/7=108/7+9/7=117/7+9/7=126/7+9/7=135/7=144/7+9/7=153/7+9/7=162/7



6.- a1= -3 an= 187 n= -75

sn = (a1+an) n = (-190)(-75) 14250= 7125


2 2 2


7.- a1= 2 an= 215 n= 164

sn = (a1+an) n = (217)(164) = 33588 =16794
             2                   2                2
8.- a1= 21 an= 276 n= 321

sn = (a1+an) n = (297)(321) = 95337 = 47668.5
             2                   2              2


9.- a1= -78 d= -49

N=a1+d (n-1)


=78+-49(n-1)


=-127(n-1)


N-1=-127


n=-127+1


n=-128


10.- a1= 345 d= -169

N=a1+d (n-1)


=345+ -169= (n-1)


=-514(n-1)


N - 1= -514


n= -514 + 1


n= -515