Հանրահաշիվ 13.04 Posted bycatherineaghajanyanApril 13, 2022Posted inՀանրահաշիվ D1=a1-a2=a2-a3 3a5-a13=10 3(a1+4d)-(a1+12d)=10 3a1+12d-a1-12d=10 20a1=10 a1=5 S7= 2a1+6d / 2 ×7 =70 S7= 8(a1+3d)×7=70 S7=a4×7=70 B2=b1×q Bn=b1×qn-¹ Bn=48 B1=3 Q=2 48= 3×2x-¹ 16=2n-¹ 2⁴=2n-1 4=n-1 n= 1+4 n=5 Share this:TwitterFacebookLike Loading... Related