Suku ke 120 dari 10,7,4,1…

B = u2 – u1 = 7-10 = -3
u120 = a + (n-1)b
u120 = 10 + (119)-3
u120 = 10 + -357
u120 = -347

semoga membantu

Un = a+(n-1)b
U120 = 10(120-1)(-3) = 10(119)(-3) = 10(-357) =-3570