Coba selesaikan tanpa subtitusi dan eliminasi
a, b, 43, c, d, e, f, g, 19, h, .... , y, z adalah barisan aritmetika.
n + o + p + q + r = ....??
a, b, 43, c, d, e, f, g, 19, h, .... , y, z adalah barisan aritmetika.
n + o + p + q + r = ....??
Dik: U3 = 43, U9 = 19
Dit: n+o+p+q+r = ..?
Un+x = 2Un - (Un-x)
U9+6 = 2U9 - (U9-6)
U15 = 2U9 - U3
U15 = 38 - 43
U15 = -5
U21 = 2U15 - U9
U21 = -10 -19
U21 = -29
n+o+p+q+r = U16+U17+U18+U19+U20 = (5/2)(U15+U21)
U16+U17+U18+U19+U20 = (5/2)(U15+U21)
U16+U17+U18+U19+U20 = (5/2)(-5+(-29))
U16+U17+U18+U19+U20 = (5/2)(-5-29)
U16+U17+U18+U19+U20 = (5/2)(-34)
U16+U17+U18+U19+U20 = -85
n+o+p+q+r = -85