find x know :
10 + 11 + 12 + 13 + 14 + . . . + x = 5106
quik reply
tìm x sao cho x+2/10^10+x+2/11^11+x+2/12^12=x+2/13^13+x+2/14^14
10 x 11 = ?
11 x 12 = ?
12 x 13 = ?
13 x 14 = ?
14 x 15 = ?
15 x 16 = ?
Ai tik mk mk tik lại!
10*11=110
11*12=132
12*13=156
13*14=182
14*15=210
15*16=240
10 x 11 = 110
11 x 12 = 132
12 x 13 = 156
13 x 14 = 182
14 x 15 = 210
15 x 16 = 240
Ai mk mk lại!
10 x 11=121
11 x 12=132
12 x 13=156
13 x 14=182
14 x 15=210
15 x 16=240
x^14-10*x^13+10*x^12-10*x^11+...+10*x^2-10*x+10 tại x=9
giúp mình với ạ
Ta có: x=9
nên x+1=10
Ta có: \(x^{14}-10x^{13}+10x^{12}-...+10x^2-10x+10\)
\(=x^{14}-x^{13}\left(x+1\right)+x^{12}\left(x+1\right)-...+x^2\left(x+1\right)-x\left(x+1\right)+x+1\)
\(=x^{14}-x^{14}-x^{13}+x^{13}+x^{12}-...+x^3+x^2-x^2-x+x+1\)
=1
Tìm x biết (x+1)/10+(x+1)/11+(x+11)/12=(x+1)/13+(x+1)/14
\(\frac{x+1}{10}+\frac{x+1}{11}+\frac{x+1}{12}-\frac{x+1}{13}-\frac{x+1}{14}=0\)
\(\left(x+1\right)\left(\frac{1}{10}+\frac{1}{11}+\frac{1}{12}-\frac{1}{13}-\frac{1}{14}\right)=0\)
=> x + 1 = 0 ( vì 1/10 + 1/11 + 1/12 - 1/13 - 1/14 khac 0 )
=> x = -1
Tìm x biết : 10+11+12+13+14+...+x = 5106
SỐ SỐ HẠNG:
(x-10)+1=x-9(số hạng)
TỔNG TRÊN LÀ:
(x+10).(x-9):2 =5106
=>(x+10).(x-9)=10212
=>(x+10).(x-9)=111.92
=>(x+10).(x-9)=(101+10).(101-9)
=>x =101
15-x/8+14-x/9=13-x/10+12-x/11. tìm x
Tính : ( 10 x 11 + 12 x 13 + 14 x 15 + ... + 22 x 23 + 24 x 25 ) x ( 13 - 13 x 1 + 10 - 10 )
Tính mau lên nhé ! Mình cần đáp án gấp !
TA có 13-13*1+10-10= 13- 13+10-10=0+0=0
(10*11+12*13+14*15+...+22*23+24*25)*0=0
* là dấu x nhe bạn
thick minh nha
( 10 x 11 + 12 x 13 + 14 x 15 + ... + 22 x 23 + 24 x 25) x ( 13 - 13 x 1 + 10 -10)
= ( 10 x 11 + 12 x 13 + 14 x 15 + ... + 22 x 23 + 24 x 25) x 0
= 0
k cho anh nha !!!!!!!!!!!!!!!! : học lớp 5 rùi
(10 x 11 + 12 x 13 + 14 x 15 + ... + 22 x 23 + 24 x 25) x ( 13 - 13 x 1 + 10 - 10)
=( 10 x 11 + 12 x 13 + 14 x 15 + ... + 22 x 23 + 24 x 25) x 0
= 0
tk nha
x+1/10+x+1/11+x+1/12=x+1/13+x+1/14
\(\frac{x+1}{10}+\frac{x+1}{11}+\frac{x+1}{12}=\frac{x+1}{13}+\frac{x+1}{14}\)
\(\Rightarrow\frac{x+1}{10}+\frac{x+1}{11}+\frac{x+1}{12}-\frac{x+1}{13}-\frac{x+1}{14}=0\)
\(\Rightarrow\left(x+1\right).\left(\frac{1}{10}+\frac{1}{11}+\frac{1}{12}-\frac{1}{13}-\frac{1}{14}\right)=0\)
mà 1/10 > 1/13; 1/11>1/14
\(\Rightarrow\frac{1}{10}+\frac{1}{11}+\frac{1}{12}-\frac{1}{13}-\frac{1}{14}\ne0\)
=> x + 1 = 0
x = -1
x+110+x+111+x+112=x+113+x+114x+110+x+111+x+112=x+113+x+114
⇒x+110+x+111+x+112−x+113−x+114=0⇒x+110+x+111+x+112−x+113−x+114=0
⇒(x+1).(110+111+112−113−114)=0⇒(x+1).(110+111+112−113−114)=0
mà 1/10 > 1/13; 1/11>1/14
⇒110+111+112−113−114≠0⇒110+111+112−113−114≠0
=> x + 1 = 0
x = -1
x+1/10 + x+1/11 + x+1/12= x+1/13 + x+1/14
\(\frac{x+1}{10}+\frac{x+1}{11}+\frac{x+1}{12}=\frac{x+1}{13}+\frac{x+1}{14}\)
\(\Rightarrow\left(x+1\right)\left(\frac{1}{10}+\frac{1}{11}+\frac{1}{12}\right)=\left(x+1\right)\left(\frac{1}{13}+\frac{1}{14}\right)\)
\(\Rightarrow x+1=0\)( do \(\frac{1}{10}+\frac{1}{11}+\frac{1}{12}\ne\frac{1}{13}+\frac{1}{14}\))
\(\Rightarrow x=-1\)