Jawab semua pertanyaan ku beri cara makasih

11. barisan geo meteri –> 5 bagian
u 1 ,u2, u3, u4, u5 
u1 = a= 5cm
u5 = 405 cm
u1= a

u5 = 405
ar^4 = 405
5 r^4 = 405
r^4 = 81
r = 3

maka panjang = a ( (r^n)-1) / r-1
= 5 / 3^5 – 1 / 3-1
= 605

12. 5(3x^2 + 4x-6) – 8x^2 + 10x – 5
= 15x^2 + 20x – 30 – 8x^2 + 10x -5
= 7x^2 + 30x – 35

13.
2(x-3) + 1 <= 3(2x+6)-3
2x-6+1<=6x+18-3
-5-15 <= 4x
x >= (-5)
jawaban d

15. P = {3,5,7,9}
 Q = {2,3,5,7,9}
Q-P = {2}

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