Khong tinh tong cua ba phan so sau, hay chung to rang tong do nho hon 2:

A= 11/ 29+ 9/ 17 + 10/ 19

Giup minh nhe

Khong tinh tong cua 3 phan so sau, hay chung to rang tong do nho hon 2:

A = 11/29 + 9/17 + 10/19

Chung minh rang tong cua mot phan so duong voi so nghich daocua no thi khong nho hon 2

chung minh rang tong cua 1 phan so duong voi so nghich dao cua no ko nho hon 2

a,timx;y sao cho 2^x=4^y-1; 27^y= 3^x+8

b,tim ba phan so biet rang tong cua chung bang 3 3/7(hon so),cac tu cua chung ti le voi 3,4,5,cac mau cua chung ti lt voi5,1,2

Biet rang : BCNN(a,b).UCLN(a,b)

a, BCNN cua hai so la 600, UCLN cua chung nho hon 10 lan BCNN. So thu 1 la 120, tim so thu 2.

b, UCLN cua hai so la 12, BCNN cua chung lon gap 6 lan UCLN . So t 1 la 24, tim so t 2

c, Tong cua hai so bang 60, tong giua UCLN va BCNN cua chung la 84. Tim hai so do.

chung to rang tong sau nho hon 2 A=6/17+9/16+11/34

Chung to rang tong cua cac phan so sau day lon hon 1/2:

S - 1/50+1/51+1/52+ ...... +1/98+1/99

chung to rang tong cua 100 so hang dau tien cua day nho hon 1/4

 1/5;1/45;1/117;1/221;1/357;...