x+(x+2)+(x+3)+...+(x+50)=1424
x+(x+2)+(x+3)+...+(x+50)=1424
Nhanh lên nha
tính bằng chách thuận tiện
1424 + 59 + 42 x 1424 - 1424
\(1424\text{×}59+42\text{×}1424-1424\)
\(=1424\text{×}59+42\text{×}1424-1424\text{×}1\)
\(=1424\text{×}\left(59+42-1\right)\)
\(=1424\text{×}100=142400\)
1424 x 59 + 42 x 1424 - 1424 =
= 1424 x ( 59 + 42 - 1 ) =
=1424 x 100 =
=142400
1424 + 59 + 42 x 1424 - 1424
1424 + 59 + 42 x 1424 - 1424 x 1
1424x ( 59 + 42 - 1 )
1424 x 100
142400
Tính:
a.[100/3]+[100/3^2]+[100/3^3]+[100/3^4]
b.[50/2]+[50/2^2]+[50/2^3]+[50/2^4]+[50/2^5]
c.[x]+[x+2/3]+[x+4/3]+[x+7/3]+[x+10/3] với x=-2,7
(50- 3 x X ) : 4 x2 -30 : 2 +2 x 7 =21
A = 33...3/50 chữ số 3 x 99...9/50 chữ số 9
( X + 2 ) + ( X+ 4) + ... + (X + 1996) = 99800
(x+2)+(x+4)+...+(x+1996) = 99800
=> (x+x+x+...+x)+(2+4+...+1996) = 99800
=> 998x + 997002 = 99800
998x = 99800 - 997002
998x = -897202
x = -897202 : 998
x = -899
cho X1+X2+X3+.......+X50+X51=0 và X1+X2=X2+X3=X49+X50=X50+X51=1.
Nhưng thầy tớ bảo x50 =26 là đúng mừ!?
cho x1+x2+x3+...+x50+x51=0 và x1+x2=x3+x4=........=x49+x50=x50+x51=1. Tính x50
Ta có:x1+x2+...+x49+x50+x51=(x1+x2)+...+(x49+x50)+x51=0
= 1+1+...+1 +x51=0 (có 25 số 1)
=25 +x51=0
=>x51=0-25= -25
Ta có:x50+x51 =1
x50+(-25)=1
x50 =1-(-25)=26
Vậy x50= 26
Vừa nãy mình viết nhầm
Tìm X
A. (X +1)+(X+2)+(X+3)+…+(X+ 100)=5750
B. X+(1+2+3+4+…+50)=2000
C. (X-1)+(X-2)+…+(X-100)=50
\(c,\)\(\left(x-1\right)+\left(x-2\right)+....+\left(x-100\right)=50\)
\(\left(x+x+...+x\right)-\left(1+2+...+100\right)=50\)
\(100x-5050=50\)
\(100x=50+5050\)
\(100x=5100\)
\(\Rightarrow x=\frac{5100}{100}=51\)
\(a,\left(x+1\right)+\left(x+2\right)+\left(x+3\right)+....+\left(x+100\right)=5750\)
\(\left(x+x+x+...+x\right)+\left(1+2+3+...+100\right)=5750\)
\(100x+5050=5750\)
\(100x=5750-5050\)
\(100x=700\)
\(\Rightarrow x=7\)
\(b,x+\left(1+2+3+...+50\right)=2000\)
\(x+\frac{\left[1+50\right]\cdot\left[\left(50-1\right)\div1+1\right]}{2}=2000\)
\(x+1275=2000\)
\(\Rightarrow x=2000-1275=725\)
c , ( x - 1 ) + ( x - 2 ) + ...... + ( x - 100 ) = 50
( x + x + ........ + ) - ( 1 + 2 + ..... + 100 ) = 50
100x - 5050 = 50
100x = 50 + 5050
100x = 5100
=> x = 5100/100 = 51
cho x1+x2+x3+.....+ x50+x51=0
biết x1+x2=x2+x3=........=x49+x50=1
tính x50
Cho x1+x2+x3+.......+x50=0
và x1+x2=x3+x4=x49+x50=x50+x51=1
Tính x50