tim n thoa
a/1+2+3+4+...+n=4950
b/2+4+6+...+2n=210
c?1+3+5+...+(2n-1) = 225
a) 2+4+6...+2. ( n - 1) + 2n= 210
b) 1+3+5+... + ( 2n - 1) =225
Giúp với ạ, đang cần gấp!!!
1+3+5+...+(2n-1) = 225
tim n thoa
Tim n biet :
a, 1+2+3+4+....+n=465
b,2+4+6+.......+2n=210
c,1+3+5+....+(2n-1)=225
tim n\(\in\)N*
a) 2+4+6+...+2n=210
b) 1+3+5+...+(2n-1)=225
tim n la so tu nhien khac 0
a.2+4+6+...+2n=210
b.1+3+5+...+(2n-1)=225
tim n thuoc N sao biet :
a) 2 + 4 + 6 + 8 + ........ + 2n = 210
b) 1 + 3 + 7 + 9 + ......... + ( 2n + 1 ) = 225
1) tim so nguyen x thoa man
a) -1-2-3-4 -...-x= 1275
b) -1-3-5-...- ( 2n -1) =-225
c) 16n -20n -24n-...-40n-44n =4800
Tìm n ∈ N* biết
a, 2 + 4 + 6 + … + 2n = 210
b, 1 + 3 + 5 +…+ (2n – 1) = 225