`15 xx x + 36 = 19 xx x`
1/2*18*17*16*15*14*xx*19=183xxx123
tính x
Tim X
a,X - 20/11 x 13 - 20/13 x 15 - 20/15 x 17 -...-20/53 x 55 = 3/11
b,1/21 + 1/28 +1/36 + ... +2/Xx(x + 1) = 2/9
Ta có : A=20/11×13 + 20/13×15 +20/15×17+...+20/53×55
A = 10 ×( 2/11×13+2/13×15+...12/53×55)
A = 10 ×(1/11-1/13+1/13-1/15+1/15-1/17+...+1/53-1/55)
A = 10 × (1/11-1/55)
A =10 × 4/55
A = 8/11
tìm X
X x 36=540 X : 53 = 60
2040 : X = 85
\(\left[{}\begin{matrix}x.36=540\Rightarrow x=540:36\Rightarrow x=15\\2040:x=85\Rightarrow x=2040:85\Rightarrow x=24\\x:53=60\Rightarrow x=60.53\Rightarrow x=3180\end{matrix}\right.\)
a: \(\Leftrightarrow x=15\)
b: x=24
X x 36= 540 X : 53 = 60
X=540 : 36 X= 60 x 53
X= 15. X= 3180
2040 : X = 85
X = 2040 : 85
X=24
3. TINH GIA TRI BIEU THUC SAU VOI X = 1 ,VA Y = 0 :
A, A= ( 15 : X + 15 xX ) + 2009 X Y
B, B= Y : ( 119 xX + 4512 ) + ( 756 : X - Y )
THay `x=1;y=0` vào biểu thức `A` ta có :
`A=(15:1+15xx1)+2990xx0`
`A=(15xx1+15xx1)+2990xx0`
`A=(15xx2)+2990xx0`
`A=30+2990xx0`
`A=30+0=30`
Thay `x=1;y=0` vào biểu thức `B` ta có :
\(B=0:\left(119\times1+4512\right)+\left(756:1-0\right)\\ B=0:4631+756\\ B=0+756=756\)
`a)` Thay `x=1;y=0` vào `A` có:
`A=(15:1+15xx1)+2009xx0`
`A=(15+15)+0=30`
`b)` Thay `x=1;y=0` vào `B` có:
`B=0:(119xx1+4512)+(756:1-0)`
`B=0+(756-0)=756`
a)\(A=\left(15:1+15\times1\right)+2009\times0=30+0=30\)
b)\(B=0:\left(119\times1+4512\right)+\left(756:1-0\right)=0+756=756\)
Bài 10:
xx + x + 5 = 125
xxx + xx + x + x = 992
4725 + xxx + xx + x = 54909
xxx - xx - x - 25 = 4430
xxx + xx + x + x + x + 1 = 1001
35655 - xxx - xx - x = 5274
( Nhớ trình bày cả cách giải giúp mk )
Tìm x
x/12=x+15/16
\(\dfrac{x}{12}=x+\dfrac{15}{16}\)
\(\Leftrightarrow\dfrac{x}{12}=\dfrac{16x+15}{16}\)
\(\Rightarrow12\left(16x+15\right)=16x\)
\(\Leftrightarrow192x+180=16x\)
\(\Leftrightarrow176x=-180\)
\(\Leftrightarrow x=-\dfrac{45}{44}\)
Vậy \(x=-\dfrac{45}{44}\)
\(\dfrac{x}{12}=\dfrac{x+15}{16}\)
\(\Rightarrow12\left(x+15\right)=16x\)
\(\Leftrightarrow12x+180=16x\)
\(\Leftrightarrow4x=180\)
\(\Leftrightarrow x=45\)
Vậy x = 45
\(\dfrac{x}{12}=\dfrac{x+15}{16}\)
\(16x=12\left(x+15\right)\)
\(16x=12x+180\)
\(4x=180\)
\(x=45\)
X x A = AA
AB x X = ABAB
ABC x X = ABCABC
ABOABO : X = AB
XX + X + 5 = 125 XXX + XX + X + X = 992
4725 + XXX + XX + X = 54909
XXX - XX - X - 25 = 4430
XXX + XX + X + X + X + 1 = 1001
35655 - XXX - XX - X = 5274
A) AB x X = ABAB => X = ABAB : AB = 101
B) X x A = AA => X = AA : A = 11
C) ABC x X = ABCABC => X = ABCABC : ABC = 1001
D) AB0AB0 : X = AB => X = AB0AB0 : AB = 10010
Các câu sau bạn tự làm nhé . Nhớ Tk cho mình nha Ok !
a, x * a = aa
x = aa : a
x = 11
b, ab * x = abab
x = abab : ab
x = 101
c, abc * x = abcabc
x = abcabc : abc
x = 1001
d, xx + x + 5 = 125
x*(11 + 1) + 5 = 125 - 5
x*12 = 120
x = 120 : 12
x = 10
e, xxx + xx + x + x = 992
x*(111 + 11 + 1 + 1) = 992
x*124 = 992
x = 992 : 124
x = 8
f, 4725 + xxx + xx + x = 54909
x*(111+11+1) = 54909 - 4725
x*123 = 50184
x = 50184 : 123
x = 408
g, xxx - xx -x - 25 = 4430
x*(111-11-1) = 4430 + 25
x*99 = 4455
x = 4455 : 99
x = 45
h, xxx + xx + x + x + x + 1 = 1001
x*(111 + 11 + 1 + 1 + 1) = 1001 - 1
x* 125 = 1000
x = 1000 : 125
x = 8
Chúc bạn học tốt
tìm x
x+x+x+15=141
(khó quá có ai giải giúp tôi với)
\(x+x+x+15=141\)
\(3x=141-15\)
\(3x=126\)
\(x=42\)
\(\text{x+x+x+15=141}\)
\(3x+15=141\)
\(3x=141-15\)
\(3x=126\)
\(x=126\div3\)
\(x=42\)
tim x;y de -xx(2-y)=10 (1-x)x(1+y)=-15