Question

Tolong bantu yah....dah limit time...

Answer 1

6. a = 2; r = 2
    Sn = a (1-r^n)/1-r
     2046 = 2.(1-2^x)/1-2
     2046 = -2(1-2^x)
     1023 = -1+2^x
       2^x = 1024
        x = 10

7. x, y, z --> barisan aritmatika
    x, (y-1), (z+3) --> barisan geometri
    z+8 = 5x --> z = 5x-8

z-y = y -x
5x-8-y = y-x
6x-8 = 2y --> y = 3x-4



5x²-5x=9x²-30x+25
4x²-25x+25=0
(x-5)(4x-5) = 0
x=5 (benar)
x=5/4 (tdk benar karena bilangan bulat)

5, 11, 17 --> beda = 6

8. a, b, c --> geometri
a, b+4, c --> aritmatika --> a+b+4+c=30 --> a+b+c=26

beda = b+4-a = c-(b+4)
2b+8=a+c
b+2b+8=a+b+c
3b+8=26
3b=18
b=6

rasio = c/b=b/a
ac=b²
ac=6²=36
a.b.c=36*6=216

perkalian tiga bilangan itu adalah 216