X x 5 + X x 7 = 96
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a)
160 : (4 × 8) = 160 : 32 = 5
160 : 4 : 8 = 40 : 8 = 5
Vậy 160 : (4 × 8) = 160 : 4 : 8.
96 : (3 × 8) = 96 : 24 = 4
96 : 3 : 8 = 32 : 8 = 4
Vậy 96 : (3 × 8) = 96 : 3 : 8.
105 : (5 × 7) = 105 : 35 = 3
105 : 5 : 7 = 21 : 7 = 3
Vậy 105 : (5 × 7) = 105 : 5 : 7.
Nhận xét: a : (b × c) = a : b : c
b)
270 : (9 × 6) = 270 : 9 : 6 = 30 : 6 = 5
420 : (7 × 3) = 420 : 7 : 3 = 60 : 3 = 20
144 : (2 × 8) = 144 : 2 : 8 = 72 : 8 = 9
![](https://rs.olm.vn/images/avt/0.png?1311)
\(x-\dfrac{1}{50}+x-\dfrac{5}{96}+x+\dfrac{9}{30}=7\\ \Leftrightarrow3x\simeq6,772\\ \Leftrightarrow x\simeq2,257\)
![](https://rs.olm.vn/images/avt/0.png?1311)
a) nếu tích = 0 => một trong hai số hạng = 0
nếu x-5=0 => x=5
nếu x-7=0 => x= 7
=> x thuộc {5;7}
b)96-3(x+1)=42
3.(x+1)=96-42=54
x+1=54:3=18
x=18-1=17
các bạn cho mk vài li-ke cho tròn 950 với
(x-5).(x-7)=0
=>x-5=0 =>x=5
hoac x-7=0=>x=7
96-3.(x+1)=42
3.(x+1) =96-42=54
(x+1) =54/3=18
x =18-1
x=7
![](https://rs.olm.vn/images/avt/0.png?1311)
5x . 5x + 1 . 7 = 875
\(\Rightarrow\) 52x + 1 = 875 : 7 = 125
\(\Rightarrow\) 52x + 1 = 53
\(\Rightarrow\) 2x + 1 = 3
\(\Rightarrow\) 2x = 2
\(\Rightarrow\) x = 1
5 + 3x + 1 = 86
\(\Rightarrow\) 3x + 1 = 81
\(\Rightarrow\) 3x + 1 = (\(\pm\)3)4
\(\Rightarrow\) x + 1 = \(\pm\)3
\(\Rightarrow\) x = 2, -4
![](https://rs.olm.vn/images/avt/0.png?1311)
a) \(96-7\left(x+1\right)=14^4:14^3\)
\(\Rightarrow96-7\left(x+1\right)=14^{4-3}\)
\(\Rightarrow96-7\left(x+1\right)=14\)
\(\Rightarrow7\left(x+1\right)=96-14\)
\(\Rightarrow7\left(x+1\right)=82\)
\(\Rightarrow x+1=\dfrac{82}{7}\)
\(\Rightarrow x=\dfrac{82}{7}-1\)
\(\Rightarrow x=\dfrac{75}{7}\)
b) \(\left(5x+3^4\right)\cdot2^4=2^6\cdot7^2\)
\(\Rightarrow5x\cdot2^4+3^4\cdot2^4=2^6\cdot7^2\)
\(\Rightarrow5x\cdot2^4+6^4=\left(2^3\cdot7\right)^2\)
\(\Rightarrow80x+1296=3136\)
\(\Rightarrow80x=1840\)
\(\Rightarrow x=\dfrac{1840}{80}\)
\(\Rightarrow x=23\)
a: =>96-7(x+1)=14
=>7(x+1)=82
=>x+1=82/7
=>x=75/7
b =>5x+81=2^2*7^2=196
=>5x=115
=>x=23
![](https://rs.olm.vn/images/avt/0.png?1311)
a: \(\dfrac{96}{\left(x-4\right)\left(x+4\right)}+\dfrac{7+x}{4-x}=\dfrac{2x-1}{x+4}-3\)
\(\Leftrightarrow\dfrac{96}{\left(x-4\right)\left(x+4\right)}-\dfrac{\left(x+7\right)\left(x+4\right)}{\left(x-4\right)\left(x+4\right)}=\dfrac{\left(2x-1\right)\left(x-4\right)}{\left(x+4\right)\left(x-4\right)}-\dfrac{3\left(x-4\right)\left(x+4\right)}{\left(x-4\right)\left(x+4\right)}\)
Suy ra: \(96-x^2-11x-28=2x^2-9x+4-3\left(x^2-16\right)\)
\(\Leftrightarrow-x^2-11x+68=2x^2-9x+4-3x^2+48\)
\(\Leftrightarrow-x^2-11x+68=-x^2-9x+52\)
=>-11x+68=-9x+52
=>-2x=-16
hay x=8(nhận)
b: \(\dfrac{2}{x-1}+\dfrac{3}{x-2}=\dfrac{3}{x-3}\)
\(\Leftrightarrow2\left(x-2\right)\left(x-3\right)+3\left(x-1\right)\left(x-3\right)=3\left(x-1\right)\left(x-2\right)\)
\(\Leftrightarrow2\left(x^2-5x+6\right)+3\left(x^2-4x+3\right)=3\left(x^2-3x+2\right)\)
\(\Leftrightarrow2x^2-10x+12+3x^2-12x+9=3x^2-9x+6\)
\(\Leftrightarrow5x^2-22x+21-3x^2+9x-6=0\)
\(\Leftrightarrow2x^2-13x+15=0\)
\(\Leftrightarrow2x^2-10x-3x+15=0\)
=>(x-5)(2x-3)=0
=>x=5(nhận) hoặc x=3/2(nhận)
![](https://rs.olm.vn/images/avt/0.png?1311)
a, 5(x – 7) = 0
x – 7 = 0
x = 7
b, 95 – 5(x+2) = 45
5(x+2) = 40
x+2 = 8
x = 6
c, 6 2 x + 2 3 + 40 = 100
6(2x+8) = 60
2x+8 = 10
x = 1
d, 3(3x+9)+6 = 96
3(3x+9) = 90
3x+9 = 30
3x = 27
x = 9
e, 2 6 + 5 + x = 3 4
5+x = 81–64
5+x = 17
x = 12
![](https://rs.olm.vn/images/avt/0.png?1311)
a) x - 96 = (443 - x) - 15
x - 96 = 443 - x - 15
x + x = 443 -15 + 96
2x = 524
x = 524 : 2
x = 262
b) (x -12) - 15 = (20 - 7) - (18 + x)
x - 12 - 15 = 20 - 7 - 18 - x
x + x = 20 - 7 - 18 + 12 + 15
2x = 22
x = 22 : 2
x = 11
c) 311 - x + 82 = 46 + (x - 21)
311 - x + 82 = 46 + x - 21
-x - x = 46 - 21 - 311 - 81
-2x = -367
x = -367 : (-2)
x = 183,5
d) -(x - 3 + 85) = (x + 70 - 71) - 5
-x + 3 - 85 = x + 70 - 71 - 5
-x - x = 70 - 71 - 5 - 3 + 85
-2x = 76
x = 76 : (-2)
x = -38
e,f làm tương tự
a) x - 96 = (443 - x) - 15
x - 96 = 443 - x - 15
x + x = 443 -15 + 96
2x = 524
x = 524 : 2
x = 262
b) (x -12) - 15 = (20 - 7) - (18 + x)
x - 12 - 15 = 20 - 7 - 18 - x
x + x = 20 - 7 - 18 + 12 + 15
2x = 22
x = 22 : 2
x = 11
c) 311 - x + 82 = 46 + (x - 21)
311 - x + 82 = 46 + x - 21
-x - x = 46 - 21 - 311 - 81
-2x = -367
x = -367 : (-2)
x = 183,5
d) -(x - 3 + 85) = (x + 70 - 71) - 5
-x + 3 - 85 = x + 70 - 71 - 5
-x - x = 70 - 71 - 5 - 3 + 85
-2x = 76
x = 76 : (-2)
x = -38
e,f làm tương tự
![](https://rs.olm.vn/images/avt/0.png?1311)
Tìm \(X\) à bạn
\(X\) x \(\left(5+7\right)=96.\)
\(X\) x \(12=96.\)
\(X=96:12.\)
\(X=8.\)