Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
-2x-(x-7)=34-(-x+25)
-2x-x+7=34+x-25
-2x-x+7-34-x+25=0
-4x-2=0
-4x=2
x=\(-\frac{1}{2}\)
#H
a) [(8x-14):2+2].31=34 <=> (4x-7+2).31=34 <=> (4x-5).31=34
124x=34+155=189 => không có x thỏa mãn
b) 3x-1=18=2.32 => không có x thỏa mãn
c) 6x+1-990=215 <=> 6x+1=215+1=216 =63 (Do 990=1)
=> x+1=3 => x=2
d) 3.2x+1-2x=I-5I <=> 3.2.2x-2x=5 <=> 2x(6-1)=5 <=> 2x=1=20
=> x=0
( x - 41 ) . 109 = 74 . 215 - 74 . 106
( x - 41 ) . 109 = 74 . ( 215 - 106 )
( x - 41 ) . 109 = 74 . 109
x - 41 = 74 . 109 : 109
x - 41 = 74
x = 74 + 41
x = 115
Vậy x = 115
=))
\(\left(x-41\right)\times109=74\times215-74\times106\)
\(\left(x-41\right)\times109=74\left(215-106\right)=74.109\)
Chia cả hai vế cho 109 \(\Rightarrow x-41=74\)
\(x=74-41=34\)
Theo đề, ta có: \(\dfrac{1+2x}{18}=\dfrac{1+4x}{34}\)
\(\Leftrightarrow34\left(1+2x\right)=18\left(1+4x\right)\)
\(\Leftrightarrow34+68x=18+72x\)
\(\Leftrightarrow34-18=72x-68x\)
\(\Leftrightarrow16=4x\)
\(\Leftrightarrow x=4\)
Khi \(x=4\) vào ta có: \(\dfrac{1+4.4}{34}=\dfrac{1+6.4}{2y^2}\Leftrightarrow\dfrac{1}{2}=\dfrac{25}{2y^2}\)
\(\Leftrightarrow2y^2=50\)
\(\Leftrightarrow y^2=50\)
\(\Leftrightarrow y=\pm5\)
a)456+[1263-x]=1362
1263-x=1362-456
1263-x=906
x=1263-906
x=357
b)22.x+4=20
22.x =20-4
22.x =16
x =16:20
x =0.8
c)34.x+1=41
34.x =41-1
34.x =40
x =40:34
x =20/17
chắc chắn 100% k cho mình nha nguyenthuyngan
456 + [ 1263 - x] = 1326
1263 - x = 1326 - 456
1263 - x = 870
x = 1326 - 870
x= 456
22x + 4 = 20
22x = 24
x = 24/22
34x + 1 = 41
=> 34x = 40
=> x = 40/34
x + 3 + 9 chia hết x + 3
9 chia hết x + 3
x + 3 thuộc Ư ( 9 )
mà Ư (9) = ( 1,3,9 )
hay x + 3 thuộc ( 1,3,9 )
ta có bảng
x + 3 1 3 9
x -2 0 6
ĐG Loại TM TM
Vậy x thuộc ( 0 , 6 )
\(1\times\left(1+1\right)+2\times\left(2+1\right)+3\times\left(3+1\right)\)
\(=1\times2+2\times3+3\times4\)
\(=2+6+12\)
\(=20\)
\(a=215\times62+42-52\times215\)
\(a=215\times\left(62-52\right)+42\)
\(a=215\times10+42\)
\(a=2150+42\)
\(a=2192\)
\(b=14\times29+14\times71+\left(1+2+3+...+99\right)\times\left(199199\times198-198198\times199\right)\)
\(b=14\times\left(29+71\right)+\left(1+2+3+...+99\right)\times\left(199\times1001\times198-198\times1001\times199\right)\)
\(b=14\times100+0\)
\(b=1400\)
1: Quá dễ
1 . (1 + 1) + 2 . (2 + 1) + 3 . (3 + 1)
= 1 . 2 + 2 . 3 + 3 . 4
= 2 + 6 + 12
= 20
2:
a = 215 . 62 + 42 - 52 . 215
= 215 . (62 - 52) + 42
= 215 . 10 + 42
= 2150 + 42
= 2192
b = 14 . 29 + 14 . 71 + (1 + 2 + 3 + ... + 99) . (199199 . 198 - 198198 . 199)
= 14 . (29 + 71) + (1 + 2 + 3 + ... + 99) . (199 . 1001 . 198 - 198 . 1001 . 199)
= 14 . 100 + (1 + 2 + 3 + ... + 99) . 0
= 1400 + 0 = 1400
\(\frac{1}{1\cdot2}+\frac{1}{2\cdot3}+\frac{1}{3\cdot4}+....+\frac{1}{x\left(x+1\right)}=\frac{215}{216}\)
\(\Leftrightarrow1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+.....+\frac{1}{x}-\frac{1}{x+1}=\frac{215}{216}\)
\(\Leftrightarrow1-\frac{1}{x+1}=\frac{215}{216}\)
\(\Leftrightarrow\frac{1}{x+1}=1-\frac{215}{216}\)
\(\Leftrightarrow\frac{1}{x+1}=\frac{1}{216}\)
\(\Leftrightarrow x=216-1=215\)
\(-2x-\left(x-17\right)=34-\left(-x+25\right)\)
\(\Leftrightarrow-2x-x+17=34+x-25\)
\(\Leftrightarrow-3x+17=x+9\)
\(\Leftrightarrow4x=8\)
\(\Leftrightarrow x=2\)
\(-2x-\left(x-17\right)=34-\left(-x+25\right)\)
\(\Rightarrow-2x-x+17=34+x-25\)
\(\Rightarrow-3x+17=34-25+x\)
\(\Rightarrow-3x+17=9+x\)
\(\Rightarrow17-9=x+3x\)
\(\Rightarrow8=4x\)
\(\Rightarrow x=2\)
Vậy \(x=2\)
( x + 34 ) . 215 = 212 . 64
( x + 81 ) . 215 = 212 . ( 23 )4
( x + 81) . 215 = 212 . 212
( x + 81 ) . 215 = 224
x + 81 = 224 : 215 = 29 = 512
x = 512 - 81 = 431
x+34=24.34.214:215
x+34=34.23
x+34=648
x=648-34=567