Question

cho biet \(1^2+2^2+3^2+.......+12^2=650\)

tinh nhanh tong\(2^2+4^2+6^2+......+24^2\)

Answer 1

2² + 4² + 6² + ... + 24²

= 2² . ( 1² + 2² + 3² + ... + 12² ) 

= 2² . 650

= 2600

Answer 2

Ta có : 2² + 4² + 6² + ... + 24²

          = 1²  . 2² + 2² . 2² + 3² . 2² + .... + 12² . 2²

          = (1² + 2² + 3² + ... + 12²) . 2²

          = 650 . 4 = 2600

Answer 3

   =2²+4²+6²+...+24²

   =2(1²⁺2²+3²+...+12²)

   =2.650

   =1300

Answer 4

Đặt A = \(1^2+2^2+3^2+...+12^2=650\)

\(2^2A=2^2\left(1^2+2^2+...+12^2\right)=2^2+4^2+...+24^2\)

\(4A=650\cdot4=2600\)

Answer 5

mk lam sai roi ket qua bang 2600 moi dung