Question

Escreva uma PA de razão -3, onde a soma dos 100 primeiros termos é -14350

POR FAVOR ME AJUDEM

Answer 1

Resposta:Segue as contas abaixo na explicação

Explicação passo-a-passo:

S100=-14350,r=-3,a1=?,a100=?

an=a1+(n-1).r                

a100=a1+(100-1).(-3)

a100=a1+99.(-3)

a100=a1-297

Sn=(a1+an).n/2

-14350=(a1+a1-297).100/2

-14350=(2.a1-297).100/2

-14350=200.a1-29700/2

200.a1-29700=(-14350).2

200.a1-29700=-28700

200.a1-29700+29700=-28700+29700

200.a1=1000

a1=1000/200

a1=5

an=a1+(n-1).r  

a100=5+(100-1).(-3)

a100=5+99.(-3)

a100=5-297

a100=-292

PA(5,2,-1,-4,-7,-10,-13,-16,-19,-22,-25,-28,-31,-34,-37,-40,-43,-46,-49,-52,-55,-58,-61,-64,-67,-70,-73,-76,-79,-82,-85,-88,-91,-94,-97,-100,-103,-106,-109,-112,-115,-,118,-121,-124,-127,-130,-,133,-136,-139,-142,-145,-148,-151,-154,-157,-160,-163,-166,-169,-172,-1,75,-178,-181,-184,-187,-190,-193,-196,-199,-202,-205,-208,-211,-214,-217,-220,-223,-226,-229,-232,-235,-238,-241,-244,-247,-250,-253,-256,-259,-262,-265,-268,-,271,-274,-,277,-280,-283,-286,-289,-292)