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tìm x,biết
5-x-16=40+x
4x-10=15-x
15-x=4x-5
x-15=6+4x
-12+x=5x-20
7x-4=20+3x
5x-7=-21-2x
x+15=20-4x
17-x=7-6x
a: Ta có: \(7x+25=144\)
\(\Leftrightarrow7x=119\)
hay x=17
b: Ta có: \(33-12x=9\)
\(\Leftrightarrow12x=24\)
hay x=2
c: Ta có: \(128-3\left(x+4\right)=23\)
\(\Leftrightarrow3\left(x+4\right)=105\)
\(\Leftrightarrow x+4=35\)
hay x=31
d: Ta có: \(71+\left(726-3x\right)\cdot5=2246\)
\(\Leftrightarrow5\left(726-3x\right)=2175\)
\(\Leftrightarrow726-3x=435\)
\(\Leftrightarrow3x=291\)
hay x=97
e: Ta có: \(720:\left[41-\left(2x+5\right)\right]=40\)
\(\Leftrightarrow41-\left(2x+5\right)=18\)
\(\Leftrightarrow2x+5=23\)
\(\Leftrightarrow2x=18\)
hay x=9
a, 4x -15=-75-x b,72-3x= 5x+8
4x+x=-75+15 -3x-5x=8-72
5x=-60 -8x=-64
x=-60:5 8x=64
x=-14 x=64:8
x=8
c,3Ix-7I=21 d,-7Ix+3I=-49
Ix-7I=21:3 Ix+3I=-49:-7
Ix-7I=7 Ix+3I=7
x-7=7 hoặc x-7=-7 x+3=7 hoặc x+3=-7
x=14 hoặc x=0 x=4 hoặc x=-10
a) \(x\in\left\{1;-1;5;-5;7;-7;35;-35\right\}\)
b) \(x\in\left\{1;-1;3;-3;5;-5;15;-15\right\}\)
c) \(x\in\left\{0;25;50;75\right\}\)
d) Ta có: \(x+16⋮x+1\)
nên \(15⋮x+1\)
\(\Leftrightarrow x+1\in\left\{1;-1;3;-3;5;-5;15;-15\right\}\)
hay \(x\in\left\{0;-2;2;-4;4;-6;14;-16\right\}\)
a) 35 \(⋮\) x \(\Rightarrow\) x \(\in\) Ư(35) = {\(\pm1;\pm5;\pm7;\pm35\)}
b) 15 \(⋮\) x \(\Rightarrow\) x \(\in\) Ư(15) = {\(\pm1;\pm3;\pm5;\pm15\)}
c) x \(⋮\) 25 \(\Rightarrow\) x \(\in\) B(25) = {\(0;25;50;75;100;...\)}
Mà x < 100 \(\Rightarrow\) x \(\in\){\(0;25;50;75\)}
d) x + 16 \(⋮\) x + 1
\(\Rightarrow\) x + 16 - (x + 1) \(⋮\) x + 1
\(\Rightarrow\) 15 \(⋮\) x + 1
\(\Rightarrow\) x + 1 \(\in\) Ư(15) = {\(\pm1;\pm3;\pm5;\pm15\)}
\(\Rightarrow\) x \(\in\) {\(0;-2;2;-4;4;-6;14;-16\)}
a) => 6x-6-5x=15
=> 6x-6+6-5x=15+6
=> 6x-5x=21
=> x=21
b) => 8x-4-7x=16
=> 8x-4+4-7x=16+4
=> 8x-7x=20
=> x=20
c) => 8-[-(2.4x)]-9x-21=31
=> 8-(-8x)-9x=31+21
=> 8-(-8x)-9x=52
=> (-8x)-9x=8-52
=> (-8x)+(-9x)=-44
=> -17x=-44
=> x=(-44):(-17)
=> x=
câu c chắc tớ làm sai
Áp dụng theo quy tắc chuyển vế
a) 5x - 16 = 40 + x
x - 5x = -16 - 40
-4x = -56
x = 14
b) 4x - 10 = 15 - x
-x - 4x = -10 - 15
-5x = -25
x = 5
c) x + 15 = 20 - 4x
-4x - x = 15 - 20
-5 x = -5
x= 1
d) 17x = 7 - 6x
-6x - 17x = -7
-23x = -7
x = 7/23
a, 5x - 16 = 41 + x
=> 5x - x = 41 + 16
=> 4x = 57
=> x = \(\frac{57}{4}\)
Vậy x = \(\frac{57}{4}\)
b) 4x - 1 =15 - x
=> 4x + x = 15 + 1
=> 5x = 16
=> \(x=\frac{16}{5}\)
Vậy \(x=\frac{16}{5}\)
c, x - 15 = 6 + 4x
=> -15 - 6 = 4x - x
=> 3x = - 21
=> x = -7
Vậy x = - 7
Có j sai mong bỏ qua
a, 5x - 16 = 41 + x b, 4x - 1 = 15 - x c, x - 15 = 6 + 4x
5x - x = 16 + 41 4x + x = 15 + 1 x - 4x = 15 + 6
4x = 57 5x = 16 - 3x = 21
x = \(\frac{57}{4}\) x = \(\frac{16}{5}\) x = - 7
Vậy x = \(\frac{57}{4}\) Vậy x = \(\frac{16}{5}\) Vậy x = - 7