Question

Mohon dibantu bro :D

Tulislah lima suku pertama barisan aritmatika yang diketahui salah satu suku dan bedanya berikut :
a. U6 = 7 dan b = 4
b.U1 = 5 dan U7 = 41
c. U19 = 91 dan U91 = 19

Answer 1

U 1 nya gak diketahui ya?
atau lupa kamu kasih tau

Answer 2

Aritmatika: Un = a+(n-1)b

a. u6 = 7, b = 4
u6 = a+5(4) = 7
a = -13
u2 = -13+4 = -9
u3 = -13+2(4) = -5
u4 = -13+3(4) = -1
u5 = -13+4(4) = 3

b. u7 = 5+6b = 41
6b = 36
b = 6
u2 = 5+6 = 11
u3 = 5+2(6) = 17
u4 = 5+3(6) = 23
u5 = 5+4(6) = 29

c. u19 = a+18b = 91
u91 = a+90b = 19
-------------------------- -
-72b = 72
b = -1

u19 = a+18b = 91
a+18(-1) = 91
a = 109
u2 = 109+(-1) = 108
u3 = 109+2(-1) = 107
u4 = 109+3(-1) = 106
u5 = 109+4(-1) = 105