Các câu hỏi tương tự
cho A = 1 -2 + 3 - 4 + 5 - 6 + ....... + 19 - 20
a, A co chi het ch2, cho 3, cho 5 khong?
b, tim x biet: 1 + 5 + 9 + 13 + 16 + ..... + x
tim x thuộc z biet:(x-15)+(x-14)+(x-13)+......+19+20=0
giai nhanh ho minh nhe
tim x biet
45-(3x+9)/13=42
(x+1)+(2x+2)+.....+(20x+20)=1050
tim x biet: 1 + 5 + 9 +13 ... + x = 501
tim x biet
|2×x-5| =13
tim x biet :1+5+9+13+16+...+x=501501
tim x thuoc Z biet 13 - | x + 5 | = 13 lam giup minh nhe cam on
Tim so nguyen x biet |5×x—3|< hoac = 13
a,Tim x biet:1+5+9+13+17+...+x=507528