( x + 1 ) + ( x + 2 ) + ( x + 3 ) + ... + ( x + 50 ) = 1375

(x + x + .... + x) + (1 + 2 + 3 + 4 + 5 + ...... + 50) = 1375

50x + 50.(50+1) : 2 = 1375

50x + 1275 = 1375

1375 - 1275 = 50x

50x = 100

x = 100 : 50

x = 2

ét ô ét haha

x + (x + 2) + (x + 4) + ... + (x + 100) = 2601

x + x + 2 + x + 4 +... + x + 100 = 2601

x × 51 + (2 + 4 + 6 + ... + 100) = 2601

x × 51+2550=2601

x × 51 = 2601 - 2550

x × 51 = 51

x = 51 : 51

x = 1