C = 3 + 32 + 33 + 34 + .... + 3100
C = (3 + 32 + 33 + 34) + ....... + (397 + 398 + 399 +3100)
C = 3(1 + 3 + 32 + 33) + ... + 397 (1 + 3 + 32 + 33)
C = 3. 40 + ... + 397 . 40
C = 40(3 + ... + 397) chia hết cho 40
C=3+3^2+3^3+....+3^100 C=(3+3^2+3^3+3^4)+........+(3^97+3^98+3^99+3^100) C=3(1+3+3^2+3^3)+..........+3^97( 1+3+3^2+3^3) C=3*40+.......+3^97*40 C=40(3+.....+3^97) chia hết cho40 nhớ l i k e cho mình nha
C=3+3^2+3^3+...+3^100
C=( 3+3^2+3^3+3^4)+(3^5+3^6+3^7+3^8)+...+(3^97+3^98+3^99+3^100)
C=3.(1+3+3^2+3^3)+3^5.(1+3+3^2+3^3)+...+3^97.(1+3+3^2+3^3)
C=3.40+3^5.40+...+3^97.40
C=40.( 3+3^5+...+3^97) chia hết cho 40
L I K E cho mình nhé