tìm x biết
\(\frac{x-1}{65}+\frac{x-3}{63}=\frac{x-5}{61}+\frac{x-7}{59}\)
Tìm x, biết:
\(\frac{x+1}{65}+\frac{x+3}{63}=\frac{x+5}{61}+\frac{x+7}{59}\)
\(\frac{x+29}{31}-\frac{x +17}{33}=\frac{x+17}{43}-\frac{x+15}{45}\)
tính nhanh
a, 2+5+11+...........+47+65
b, 1+6+11+16+......+46+51
c, 3+12+48+.......+3072+12288
d, 49-51+53-55+57-59+61-63+65
a) 5+8+11+...+41
b) 65-63+61-59+...+53-51+49
Tính nhanh các tổng sau
a, 1+2+3+4+5+...+n
b, 1+3+5+7+...+(2n-1)
c, 2+4+6+8+...+2n
d, 2+5+11+...+47+65
e, 3+12+48+...+3072+12288
g, 2+5+7+12+...+81+131
h, 49-51+53-55+57-59+61-63+65
1+2+3+........+n
1+3+5+7+.....(2n - 1)
2+4+6+8+....+2n
1+6+11+16+.......+46+51
2+5+11+.......+47+56
3+12+48+.......+3072+12288
2+5+7+12+........+81+131
49-51+53-55+57-59+61-63+65
Bạn nào biewts giúp mk với
49-51+53-55+57-59+61-63+65
tính nhanh
1+3-5-7+9+11-13-15+17+...-57-59+61+63
tính nhanh
49-51+53-55+57-59+61-63+65
