Question

Ika suku ke-6 dari barisann aritmatika sama dengan 27 dan suku ke-12 adalah 48. carila suku ke-10..

Answer 1

Un = a + (n-1)b

U(6) = a + (6-1)b
27 = a + 5b

U(12) = a + (12-1)b
48 = a + 11b
a = 48-11b

substitusi

27 = a + 5b
27 = 48 - 11b + 5b
27 = 48 -6b
-6b = 27 - 48
-6b = -21
b = 21/6
substisu lagi

a = 48 -11b
a = 48 - 11(21/6)
a = 48 - 231/6
a = 57/6

U10 = a + (10 -1)b
U10 = 57/6 + (9) 21/6
U10 = 57/6 + 189/6
U10 = 246/6
U10 = 41

Answer 2

[tex]U_{6} =a+5b=27 \\ U_{12} =a+11b=48 \\ U_{12}-U_{6}=a+11b-(a+5b)=48-27 \\ 6b=21=>b= \frac{7}{2} \\ a+5b=27=>a+5.\frac{7}{2}=27=>a+\frac{35}{2}= \frac{54}{2}=>a = \frac{54}{2}-\frac{35}{2}=\frac{19}{2} \\ U_{10}=a+9b=\frac{19}{2}+9.\frac{7}{2}=\frac{19}{2}+\frac{63}{2}=\frac{82}{2}=41[tex]