barisan aritmatika jika U3=-22 dan U10=-47 tentukan U25

Dik :
U3 = a + ( 3 - 1).b
U3 = a + 2b = -22

U5 = a + (5 - 1) .b
U5 = a + 4b = -47

eliminasi :
a + 2b = -22
a + 4b = -47
=> -2b = 25
b = 25/-2
b = -12.5

b = -12.5
a + 2b = -22
a + 2.(-12.5) = -22
a + (-25) = (-22)
a = (-22) + 25
a = 3

U25 = a + (n - 1). b
U25 = 3 + (25 - 1). (-12.5)
U25 = 3 + 24. (-12.5)
U25 = 3 + (-300)
U25 = (-297)

Jika jawaban ini membantumu, jadiin jawaban terbaik :)