Tìm x:
( 2x - 2 ) 12 = 16
52x+1 = 5x . 2 = 375
Tìm x biết :
a, 4.(18 - 5x) - 12.(3x - 7) = 15.(2x - 16) - 6(x + 14)
b, 5.(3x + 5) - 4.(2x - 3) = 5x + 3.(2x + 12) + 1
c, 2.(5x - 8) - 3.(4x - 5) = 4.(3x - 4) + 11
d, (3x + 2)(2x + 9) - (x + 2)(6x + 1) = (x + 1) - (x - 6)
e, (8x - 3)(3x + 2) - (4x + 7)(x + 4)= (2x + 1)(5x - 1) - 33
Noob ơi, bạn phải đưa vào máy tính ý solve cái là ra x luôn, chỉ tội là đợi hơi lâu
a, 4.(18 - 5x) - 12(3x - 7) = 15(2x - 16) - 6(x + 14)
=> 72 - 20x - 36x + 84 = 30x - 240 - 6x - 84
=> (72 + 84) + (-20x - 36x) = (30x - 6x) + (-240 - 84)
=> 156 - 56x = 24x - 324
=> 24x + 56x = 324 + 156
=> 80x = 480
=> x = 480 : 80 = 6
Vậy x = 6
b, 5(3x + 5) - 4(2x - 3) = 5x + 3(2x + 12) + 1
=> 15x + 25 - 8x + 12 = 5x + 6x + 36 + 1
=> (15x - 8x) + (25 + 12) = 11x + 37
=> 7x + 37 = 11x + 37
=> 11x - 7x = 0
=> x = 0
Tìm x biết:
a) 4(18-5x) - 12(3x-7) = 15(2x-16) - 6(x+14)
b) 5(3x+5) - 4(2x-3) = 5x+3(2x+12)+1
c)2(5x-8) - 3(4x-5) = 4(3x-4) + 11
d) 5x-3 {4x-2 [4x-3(5x-2)]}=182
3,26 + 4/5 =?
làm nhanh lên giúp mình nhé
3,26+4/5=3,26+0,8=3,34
K cho mình cái
\(2\left(5x-8\right)-3\left(4x-5\right)=4\left(3x-4\right)+11\)
\(\Leftrightarrow10x-16-12x+15=12x+16+11\)
\(\Leftrightarrow-2x-1=12x+27\Leftrightarrow-14x-28=0\Leftrightarrow x=-2\)
tìm số tự nhiên x thỏa mãn
a, (2x -25) : 3 = 27
b, (x-3) . ( 8-x ) = 0
c, 889 - 5x - 2x = 375
d, 516 - ( 246 + 3x ) = 26
e, x + 1 + 2 + 3 + 4 + .....+49 + 50 = 1500
a) ( 2x - 25 ) : 3 = 27
( 2x - 25 ) = 81
2x = 81 + 25
2x = 106
x = 53
b) ( x - 3 ) ( 8 - x ) = 0
\(\Rightarrow\orbr{\begin{cases}x-3=0\\8-x=0\end{cases}}\)\(\Rightarrow\orbr{\begin{cases}x=3\\x=8\end{cases}}\)
d) 516 - ( 246 + 3x ) = 26
246 + 3x = 490
3x = 244
x =
a)(2x - 25) : 3 = 27
=> 2x - 25 = 27 . 3
=> 2x - 25 = 81
=> 2x = 81 + 25 = 106
=> x = 106 : 2 = 53
b)(x - 3).(8 - x) = 0
=> x - 3 = 0 hoặc 8 - x = 0
=> x = 3 hoặc x = 8
c) 889 - 5x - 2x = 375
=>889 - 7x = 375
=>7x = 889 - 375
=>7x = 514
=>x = 514/7
d) 516 - ( 246 + 3x ) = 26
=> 246 + 3x = 516 - 26
=> 246 + 3x = 490
=> 3x = 490 - 246
=> 3x = 244
=> x = 244/3
e) x + 1 + 2 + 3 + ... + 50 = 1500
=>x + (1 + 2 + 3 + ... + 50) = 1500
=>x + 50.(50+1):2 = 1500
=>x + 1275 = 1500
=>x = 1500 - 1275
=>x = 225
Tìm số tự nhiên x thỏa mãn :
a , ( 2x - 25 ) : 3 = 27
2x - 25 = 27 × 3
2x - 25 = 81
2x = 81 + 25
2x = 106
x = 106 : 2
x = 53
Vậy x = 53
b, ( x - 3 ) . ( 8 - x ) = 0
<=> x - 3 = 0 hoặc 8 - x = 0
<=> x = 0 + 3 hoặc x = 8 - 0
<=> x = 3 hoặc x = 8
Vậy x € { 3 ; 8 }
Tìm x
12(x – 1) = 0
45 + 5(x – 3) = 70
3.x – 18 : 2 = 12
5x + 2x = 62 - 50
5x + x = 150 : 2 + 3
\(a,12\left(x-1\right)=0\\ x-1=0\\ x=1\\ b,45+5\left(x-3\right)=70\\ 5\left(x-3\right)=25\\ x-3=5\\ x=8\\ c,3.x-18:2=12\\ 3.x-9=12\\ 3.x=21\\ x=7\)
12(x-1)=0
(x-1)=0:12
x-1=0
x=0+1
x= 1
Vậy x= 1
12 ( x - 1 ) = 0
x - 1 = 0 : 12
x - 1 = 0
=> x = 1
Tìm x:
a) 4(18 - 5x) - 12(3x - 7) = 15(2x - 16) - 6(x + 14)
b) 5(3x + 5) - 4(2x - 3) = 5x + 3(2x + 12) + 1
c) 2(5x - 8) - 3(4x - 5) = 4(3x - 4) +11
d) 5x - 3{4x - 2[4x - 3(5x - 2)]} = 182
a, \(4\left(18-5x\right)-12\left(3x-7\right)=15\left(2x-16\right)-6\left(x+14\right)\)
\(\Leftrightarrow72-20x-36x+84=30x-240-6x-84\)
\(\Leftrightarrow156-56x=24x-324\)
\(\Leftrightarrow-80x+480=0\Leftrightarrow x=-6\)
b, \(5\left(3x+5\right)-4\left(2x-3\right)=5x+3\left(2x-12\right)+1\)
\(\Leftrightarrow15x+25-8x+12=5x+6x-36+1\)
\(\Leftrightarrow7x+37=11x-35\)
\(\Leftrightarrow-4x+72=0\Leftrightarrow x=18\)
c, \(2\left(5x-8\right)-3\left(4x-5\right)=4\left(3x-4\right)+11\)
\(\Leftrightarrow10x-16-12x+15=12x-16+11\)
\(\Leftrightarrow-2x-1=12x-5\)
\(\Leftrightarrow-14x+4=0\Leftrightarrow x=\frac{2}{7}\)
d, \(5x-3\left\{4x-2\left[4x-3\left(5x-2\right)\right]\right\}=182\)
\(\Leftrightarrow5x-3\left[4x-15x+6\right]=182\)
\(\Leftrightarrow5x-3\left(-11x+6\right)=182\)
\(\Leftrightarrow5x+33x-18-182=0\)
\(\Leftrightarrow38x-200=0\Leftrightarrow x=\frac{100}{19}\)
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Tìm điều kiện của x để phân thức sau xác định:
a)\(\dfrac{3x^2+6x+12}{x^3-8}\)
b)\(\dfrac{x^2+2x+5}{2x^2+5x+3}\)
c)\(\dfrac{5x+1}{x^2-4}\)
`a,x^3-8 ne 0`
`=>x^3 ne 8`
`=>x ne 2`
`b,2x^2+5x+3 ne 0`
`=>2x^2+2x+3x+3 ne 0`
`=>2x(x+1)+3(x+1) ne 0`
`=>(x+1)(2x+3) ne 0`
`=>x ne -1,-3/2`
`c,x^2-4 ne 0`
`=>x^2 ne 4`
`=>x ne 2,-2`
a) ĐK:
\(x^3-8\ne0\\ \Leftrightarrow x\ne2\)
b) ĐK:
\(2x^2+5x+3\ne0\\ \Leftrightarrow\left[{}\begin{matrix}x\ne-1\\x\ne-\dfrac{3}{2}\end{matrix}\right.\)
c) ĐK:
\(x^2-4\ne0\\ \Leftrightarrow x\ne\pm2\)
a) ĐKXĐ: \(x\ne2\)
b) ĐKXĐ: \(x\notin\left\{-\dfrac{3}{2};-1\right\}\)
c) ĐKXĐ: \(x\notin\left\{2;-2\right\}\)
Bài 1 : Tìm x,yez
1, 3 - | 2x + 1 | = ( - 5 )
2, 12 + | 3 - x | = 9
3 , | x + 9 | = 12 + ( - 9 ) + 2
4 , 5x - 16 = 40 + x
5 , 5x - 7 = - 21 - 2x
6, ( 2x - 1 ) ( y - 2 ) = 12
nhờ cấc a/c giúp e vs ạk e đang cần gấp
6, ( 2x + 1 ) ( y - 2 ) = 12
1. \(3-|2x+1|=-5\)
\(\Rightarrow|2x+1|=8\)
\(\Rightarrow\orbr{\begin{cases}2x+1=8\\2x+1=-8\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}2x=7\\2x=-9\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}x=\frac{7}{2}\\x=-\frac{9}{2}\end{cases}}\)
Vậy \(x\in\left\{\frac{7}{2};-\frac{9}{2}\right\}\)
2.\(12+|3-x|=9\)
\(\Rightarrow|3-x|=-3\)
Mà \(|3-x|\ge0\forall x\)
\(\Rightarrow\)Vô lí
Vậy không có x
3.\(|x+9|=12+\left(-9\right)+2\)
\(\Rightarrow|x+9|=5\)
\(\Rightarrow\orbr{\begin{cases}x+9=5\\x+9=-5\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}x=-4\\x=-14\end{cases}}\)
Vậy \(x\in\left\{-4;-14\right\}\)
4.\(5x-16=40+x\)
\(\Rightarrow5x-x=40+16\)
\(\Rightarrow4x=56\)
\(\Rightarrow x=14\)
Vậy \(x=14\)
5.\(5x-7=-21-2x\)
\(\Rightarrow5x+2x=-21+7\)
\(\Rightarrow7x=-14\)
\(\Rightarrow x=-2\)
Vậy \(x=-2\)
6.\(\left(2x-1\right)\left(y-2\right)=12\)
Vì \(x,y\inℤ\)nên \(2x-1;y-2\inℤ\)
\(\Rightarrow2x-1;y-2\inƯ\left(12\right)=\left\{\pm1;\pm2;\pm3;\pm4;\pm6;\pm12\right\}\)
Ta có bảng : (em tự xét bảng nhé)
Tìm số nguyên x
a)(2x+5)÷(2x+1)
b)(3x+5)÷(x+1)
c)(3x+8)÷(x-1)
d)(5x+12)÷(x-2)
e)(7x-12)÷(x+16)
a) \(\dfrac{2x+5}{2x+1}=\dfrac{2x+1+4}{2x+1}=\dfrac{2x+1}{2x+1}+\dfrac{4}{2x+1}=1+\dfrac{4}{2x+1}\)
Để \(\dfrac{2x+5}{2x+1}\in Z\) thì \(\dfrac{4}{2x+1}\in Z\)
\(\Rightarrow4\) ⋮ \(2x+1\)
\(\Rightarrow2x+1\inƯ\left(4\right)=\left\{1;-1;2;-2;4;-4\right\}\)
\(\Rightarrow2x\in\left\{0;-2;1;-3;3;-5\right\}\)
\(\Rightarrow x\in\left\{0;-1;\dfrac{1}{2};-\dfrac{3}{2};\dfrac{3}{2};-\dfrac{5}{2}\right\}\)
Mà x nguyên \(\Rightarrow\text{x}\in\left\{0;-1\right\}\)
b) \(\dfrac{3x+5}{x+1}=\dfrac{3x+3+2}{x+1}=\dfrac{3\left(x+1\right)+2}{x+1}=\dfrac{3\left(x+1\right)}{x+1}+\dfrac{2}{x+1}=3+\dfrac{2}{x+1}\)
Để \(\dfrac{3x+5}{x+1}\in Z\) thì \(\dfrac{2}{x+1}\in Z\)
\(\Rightarrow2\) ⋮ \(x+1\)
\(\Rightarrow x+1\inƯ\left(2\right)=\left\{1;-1;2;-2\right\}\)
\(\Rightarrow x\in\left\{0;-2;1;-3\right\}\)
c) \(\dfrac{3x+8}{x-1}=\dfrac{3x-3+11}{x-1}=\dfrac{3\left(x-1\right)+11}{x-1}=\dfrac{3\left(x-1\right)}{x-1}+\dfrac{11}{x-1}=3+\dfrac{11}{x-1}\)
Để: \(\dfrac{3x+8}{x-1}\in Z\) thì \(\dfrac{11}{x-1}\in Z\)
\(\Rightarrow11\) ⋮ \(x-1\)
\(\Rightarrow x-1\inƯ\left(11\right)=\left\{1;-1;11;-11\right\}\)
\(\Rightarrow x\in\left\{2;0;12;-10\right\}\)
d) \(\dfrac{5x+12}{x-2}=\dfrac{5x-10+22}{x-2}=\dfrac{5\left(x-2\right)+22}{x-2}=\dfrac{5\left(x-2\right)}{x-2}+\dfrac{22}{x-2}=5+\dfrac{22}{x-2}\)
Để: \(\dfrac{5x+12}{x-2}\in Z\) thì \(\dfrac{22}{x-2}\in Z\)
\(\Rightarrow22\) ⋮ \(x-2\)
\(\Rightarrow x-2\inƯ\left(22\right)=\left\{1;-1;2;-2;11;-11;22;-22\right\}\)
\(\Rightarrow x\in\left\{3;1;4;0;13;-9;24;-20\right\}\)
e) \(\dfrac{7x-12}{x+16}=\dfrac{7x+112-124}{x+16}=\dfrac{7\left(x+16\right)-124}{x+16}=\dfrac{7\left(x+16\right)}{x+16}-\dfrac{124}{x+16}=7-\dfrac{124}{x+16}\)
Để \(\dfrac{7x-12}{x+16}\in Z\) thì \(\dfrac{124}{x+16}\in Z\)
\(\Rightarrow124\) ⋮ \(x+16\)
\(\Rightarrow x+16\inƯ\left(124\right)=\left\{1;-1;2;-2;4;-4;31;-31;62;-62;124;-124\right\}\)
\(\Rightarrow x\in\left\{-15;-17;-14;-18;-12;-20;15;-47;46;-78;108;-140\right\}\)
tìm x:2x+2/5x-3=2x+12/5x+18