Ta có :
\(\frac{\left(x+1\right)x}{2}=509545\)
\(\Rightarrow\left(x+1\right)x=1019090\)
Mà: 1009x1010=1019090
=> x=1009
http://olm.vn/hoi-dap/question/44649.html
1. -2/9 x 15/17 + -2/9 x 2/17
2. -5/3 x 6/5 + -7/9 x 3/10
3. 15/20 x 7/5 + -9/7 x -6/4
4.-25/13 x 5/19 + -25/13 x 14/19
5 -7/13 x 13/5 + -9/7 x 5/3
1. -2/9 x 15/17 + -2/9 x 2/17
2. -5/3 x 6/5 + -7/9 x 3/10
3. 15/20 x 7/5 + -9/7 x -6/4
4.-25/13 x 5/19 + -25/13 x 14/19
5 -7/13 x 13/5 + -9/7 x 5/3
6. 27/35 x 5/9 - 2/7 x -7/5
7. 10/13 x 13/5 + {-9/5} x 10/3
8. 100/27 x 9/20 + 40% x 5/3
9. 1,5 x 5/12 + 1/4 x 3/4
10. 2 1/2 x 7/5 + {-9/10} x 2/3
11. X + 45% = 2 1/2 -5/3
12. 80% + X = -5/2 + 3/4
13. 4/25 - X =-5/2 + -3/10
(13+2/9 - 15+2/3).(302 - 54)
(18+3/7 - 17+1/4).(25-12.52)
x Y=
2/11+3/13+4/15+5/17
4+1/11+5/13+9/15+13/17
bài 1 Tính:
a) 5/17 * 8/-7+8/17*-7/3+-7/3*4/17
b) -10/13 + 5/17 - 3/13 + 12/17 - 11/20
giúp tớ vs ạ. Tớ CẢM ƠN
*tớ thêm một câu nữa ạ
c) 5/9 * 7/13 + 5/9 * 9/13 + 3/13 * -5/9
\(\dfrac{9}{17}\) x \(\dfrac{21}{13}\) + \(\dfrac{9}{17}\) x \(\dfrac{5}{13}\) - \(\dfrac{9}{17}\) x 2
Các bạn giải giúp mình chi tiết nha! Tks
1+5+9+13+17+...+x=4950
1+5+9+13+17+...+x =4950
\(1+5+9+13+17+...+x=4950\)
Tìm x biết: 1 + 5 + 9 + 13 + 17 +…. + x =507528
