Tìm x biết (x+1)+(x+2)+...+(x+99)=6138
Tìm x bt:
a) x-1/99 + x-2/98 + x-3/97 + x-4/96 = 4
b) x+1/99 + x+2/98 + x+3/97 = 3
c) x-1/99 + x-2/49 + x-4/32 = 6
Giúp mik với! Th5 mik mới nộp nhưng mong các bn giúp mik!
Tìm x:
a)39.(5-2x)=39
b)x+(x+1)+(x+3)+...+(x+99)=1240
c) (x+1)+(x+3)+...+(x+99)=7500
d)1+2+3+...+100=1/2.x(x+1). (x thuộc N)
tính nhanh
A = 1 x 2 x3 + 2 x 3 x 4 + ..... + 99 x 100 x 101
B = 1 x 2 + 2 x 3 + 3 x 4 +.......+ 999 x 1000
C = 1 + 4 + 9 + 16 + 25 + 36 + ....+ 10000
D = 1 + 2^2 + 3^2+ 4^2+ 5^2 + ... + 99^2
a ) A = 1/3 + 1/15 + 1/35 + 1/63 + 1/99 + 1/143
b) x + ( x + 1 ) + ( x + 2 ) + ....+ ( x + 99 ) = 14950
éc ô éc
Tính nhanh :
a) 1 / 1 x 2 + 1/ 2 x 3 + 1/ 3 x 4 + .............................................................................................................. + 1 / 99 x100
b) 2 / 1 x 3 + 2 / 3 x 5 + 2 / 5 x 7 + ............................................................................................................ + 2 / 97 x 99
c) 4 / 5 x 7 + 4 / 7 x 9 + 4 / 9 x 11 + .......................................................................................................... + 4 / 59 x 61
Giúp mình nha mình tick cho.
a,x/3=2/3+-1/7;b, 2/3*x-4/3=-3/10 c, (2/1*3+2/3*5+2/5*7+ ....+2/97*99) -x=-100/99
a ) 1 + 2 + 3 + 4 +.................+ 98 + 99
b ) 2 + 4 + 6 +.............+ 100
c ) 1 x 2 + 2 x 3 + ............+ 99 x 100
tìm x thuộc Z
a)1+2+3+.........+x=5050
b)1/2+1/6+........1x2+x=99/100
c)1/6+1/12+.......1/x2-x=59/100
d)x-2017+x-2016+.........+99+100=0
g)x-1+x-2+x-3+.......x-2017=0