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ALIYU BALA USMAN
Answers (1)
T3=ar^2= 28 T4=ar^3= -56 r= -56/28; r=-2 From T3=ar^2 =28 T3=a(-2)^2= 28 4a=28 a=7 a=7, r=-2 The sum of a G.P Sn =a(1-r^n)/1-r Sn=7[(1-(-2)^n]/1-(-2) Sn=7(1+2)^n/1+2 Sn=7(3)^n/3 Sn=21^n/3 Sn=7^n.
