Em uma P A, o nono termo é 33 e o sexto, 42 Determine o primeiro termo e a razão dessa P A

Em uma P A, o nono termo é 33 e o sexto, 42 Determine o primeiro termo e a razão dessa P A



  • Certified answers contain reliable, trustworthy information vouched for by a hand-picked team of experts. Brainly has millions of high quality answers, all of them carefully moderated by our most trusted community members, but certified answers are the finest of the finest.
    Para encontrar basta fazer:

    a=33
    a=42
    _________
    a+8r=33
    a+5r=42
    _________
    3r=-9
    r=-9/3
    r=-3

    Com isso, sei que a razo igual a -3. E para achar o primeiro termo, basta substituir:

    a+8r=33
    a+8*(-3)=33
    a-24=33
    a=33+24
    a=57

    Logo, sei que o primeiro termo 57 e que a razo -3

  • Certified answers contain reliable, trustworthy information vouched for by a hand-picked team of experts. Brainly has millions of high quality answers, all of them carefully moderated by our most trusted community members, but certified answers are the finest of the finest.
    a1 + 8r = 33
    a1 + 5r = 42(-1)

    a1 + 8r = 33
    -a1 — 5r = — 42
    3r = — 9
    r = — 3

    a1 = 33 — 8r
    a1 = 33 — 8(-3)
    a1 = 33+ 24
    a1 = 57


Добавить комментарий

54 + = 55