Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
a) 124 + (118 - x) = 217
118 - x = 217 - 124
118 - x = 93
x = 118 - 93
x = 25
b) 156 - (x + 61) = 82
x + 61 = 156 - 82
x + 61 = 74
x = 74 - 61
x = 13
c) 219 - 7(x + 1) = 100
7(x + 1) = 219 - 100
7(x + 1) = 119
x + 1 = 119 : 7
x + 1 = 17
x = 17 - 1
x = 16
d) (3x - 6).3 = 3⁴
3x - 6 = 3⁴ : 3
3x - 6 = 3³
3x - 6 = 27
3x = 27 + 6
3x = 33
x = 33 : 3
x = 11
e) 231 - (x - 6) = 1339 : 13
231 - (x - 6) = 103
x - 6 = 231 - 103
x - 6 = 128
x = 128 + 6
x = 134
a) 124 + (118 - x) = 217
118 - x = 217 - 124
118 - x = 93
x = 118 - 93
x = 25
b) 156 - (x + 61) = 82
x + 61 = 156 - 82
x + 61 = 74
x = 74 - 61
x = 13
c) 219 - 7(x + 1) = 100
7(x + 1) = 219 - 100
7(x + 1) = 119
x + 1 = 119 : 7
x + 1 = 17
x = 17 - 1
x = 16
d) (3x - 6) . 3 = 34
(3x - 6) . 3 = 81
(3x - 6) = 81 : 3
(3x - 6) = 27
3x = 27 + 6
3x = 33
x = 33 : 3
x = 11
e) 231 - (x - 6) = 1339 : 13
231 - (x - 6) = 103
(x - 6) = 231 - 103
x - 6 = 128
x = 128 + 6
x = 134
a. 4(2x+7)-3(3x-2)=24
=> 8x+28-9x+6=24
=> -x+34=24
=> -x=-10=> x=10
b. 2(x-1)+3(x-2)=x-4
=> 2x-2+3x-6=x-4
=> 5x-8=x-4
=> 5x-x=-4+8
=> 4x=4=> x=1
c. [124-(20-4x)]:30+7=11
=> (124-20+4x):30=4
=> (104+4x):30=4
=> 104+4x=120
=> 4x=96 => x=24
\(3^x+3^{x+1}=3^8.2+2.3^8.2017^0\)
\(3^x+3^x.3=3^8.2^2\)
\(3^x=3^8.2^2:3\)
\(3^x=3^7.2^2\)
3x+3x+1=38.2+2.38.201703x+3x+1=38.2+2.38.20170
3x+3x.3=38.223x+3x.3=38.22
3x=38.22:33x=38.22:3
3x=37.223x=37.22
b: Ta có: 7x-8=713
nên 7x=721
hay x=103
c: Ta có: x-36:18=12
nên x-2=12
hay x=14
d: Ta có: (x-36):18=12
nên x-36=216
hay x=252
\(\frac{3x}{2.5}+\frac{3x}{5.8}+\frac{3x}{8.11}+\frac{3x}{11.14}=\frac{1}{21}\)
=> \(x\left(\frac{3}{2.5}+\frac{3}{5.8}+\frac{3}{8.11}+\frac{3}{11.14}\right)=\frac{1}{21}\)
=> \(x\left(\frac{1}{2}-\frac{1}{5}+\frac{1}{5}-\frac{1}{8}+\frac{1}{8}-\frac{1}{11}+\frac{1}{11}-\frac{1}{14}\right)=\frac{1}{21}\)
=> \(x\left(\frac{1}{2}-\frac{1}{14}\right)=\frac{1}{21}\)
=> \(x.\frac{3}{7}=21\)
=> x = 49
Vậy x = 49
a) x + 118 = 218
x = 218 – 118
x = 100
b) 18 – x = -17
X = 18 – (-17)
X = 35
c) (-18) – x = -17
X = (-18) – (-17)
X = -1
d)124 + (118 – x) = 217
118 – x = 93
X = 118 – 93
X = 25
e) (3x – 6).3 = 34
(3x – 6).3 = 81
3x – 6 = 27
3x = 33
ð X = 11
g) 23.(42 – x) = 46
42 – x = 2
ð X = 40
h) 84 – (3x + 8) = 34
3x + 8 = 84 – 34
3x + 8 = 50
3x = 50 – 8
3x = 42
X = 42 : 3
ð X = 14
i) 3.(2x + 1) – 19 = 14
3.(2x + 1) = 14 + 19
3.(2x + 1) = 33
2x + 1 = 33 : 3
2x + 1 = 11
2x = 11 – 1
2x = 10
X = 10 : 2
ð X = 5
k) 6x – 302 = 23.5
6x – 302 = 40
6x = 40 + 302
6x = 342
X = 342 : 6
ð X = 57
m) (x – 1)2 = 81
(x – 1)2 = 92
ð X – 1 = 9
ð X = 9 + 1
ð X = 10
n) 2x+1 – 5 = 27
2x+1 = 27 + 5
2x+1 = 32
2x+1 = 25
ð X = 4
`x . 3/7 = 2/3`
`=>x= 2/3 : 3/7`
`=>x= 2/3 . 7/3`
`=>x=14/9`
`-----------`
`x : 8/11 = 11/3`
`=>x= 11/3 . 8/11`
`=>x= 88/33`
`=>x=8/3`
`-----------`
`4/7 . x - 2/3 = 1/5`
`=> 4/7 . x = 1/5 +2/3`
`=>4/7 . x =3/15 + 10/15`
`=>4/7 . x =13/15`
`=>x= 13/15 : 4/7`
`=>x= 13/15 xx 7/4`
`=>x= 91/60`
Lời giải:
$x.\frac{3}{7}=\frac{2}{3}$
$x=\frac{2}{3}: \frac{3}{7}=\frac{14}{9}$
-----------
$x: \frac{8}{11}=\frac{11}{3}$
$x=\frac{11}{3}.\frac{8}{11}=\frac{8}{3}$
-----------
$\frac{4}{7}x-\frac{2}{3}=\frac{1}{5}$
$\frac{4}{7}x=\frac{2}{3}+\frac{1}{5}=\frac{13}{15}$
$x=\frac{13}{15}: \frac{4}{7}=\frac{91}{60}$
a) ta có: 4x+9y=45
=> 4x=45-9y
=> 4x=9.(5-y)
ta thấy: 4x chia hết cho 4 =>9.(5-y) cũng phải chia hết cho 4
mà ƯCLN(4,9)=1 =>5-y phải chia hết cho 4 =>5-y thuộc Ư(4)
ta có Ư(4)={0;4;8;12;.....}
vì y là số tự nhiên => 5-y=0 hoặc 5-y=4
=>y=5 hoặc y=1
+) 5-y=0 =>9.(5-y)=9.0=0 =>4x=0 =>x=0:4=0
+) 5-y=4 =>9.(5-y)=9.4=36 =>4x=36 =>x=9
Vậy (x;y)=(0;5);(9;1)
a) \(10⋮\left(x-1\right)\) (đkxđ \(x\ne1\))
\(\Rightarrow x-1\in\left\{-1;1;-2;2;-5;5;-10;10\right\}\)
\(\Rightarrow x\in\left\{0;2;-1;3;-4;6;-9;11\right\}\)
b) \(\left(x+5\right)⋮\left(x-2\right)\left(đkxđ,x\ne2\right)\)
\(\Rightarrow\left(x+5\right)-\left(x-2\right)⋮\left(x-2\right)\)
\(\Rightarrow x+5-x+2⋮\left(x-2\right)\)
\(\Rightarrow7⋮\left(x-2\right)\)
\(\Rightarrow x-2\in\left\{-1;1;-7;7\right\}\)
\(\Rightarrow x\in\left\{1;3;-5;9\right\}\)
c) \(\left(3x+8\right)⋮\left(x-1\right)\left(đkxd,x\ne1\right)\)
\(\Rightarrow\left(3x+8\right)-3\left(x-1\right)⋮\left(x-1\right)\)
\(\Rightarrow3x+8-3x+3⋮\left(x-1\right)\)
\(\Rightarrow11⋮\left(x-1\right)\)
\(\Rightarrow x-1\in\left\{-1;1;-11;11\right\}\)
\(\Rightarrow x\in\left\{0;2;-10;12\right\}\)
a) x∈{0;2;−1;3;−4;6;−9;11}
b) x∈{1;3;−5;9}
c) x ∈ {0;2;−10;12}
=> 8+6x+2=124
=> 6x+10=124
=> 6x=114
=> x=19
8 + 2(3x + 1) = 124
\(\Leftrightarrow\)2(3x + 1) = 124 - 8 = 116
\(\Leftrightarrow\)3x + 1 = 116 : 2 = 58
\(\Leftrightarrow\)3x = 58 - 1 = 57
\(\Leftrightarrow\)x = 57 : 3 = 19
Vậy x = 19