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a) 17x + 33x = 100
<=> 50x = 100
<=> x = 2
Vậy x = 2
b) 23x + 15 ( x + 7) = 105
<=> 23x + 15x + 105 = 105
<=> 38x = 0
<=> x = 0
Vậy x = 0
c) 32 (x - 11) + 4x = 152
<=> 32x - 352 + 4x = 152
<=> 36x = 504
<=> x = 14
Vậy x = 14
d) 51 ( 3x + 5) - 406 = 22 (3x +50)
<=> 153x + 255 - 406 = 66x + 1100
<=> 87x = 1251
<=> x = \(\frac{1251}{87}\)
Vậy x = \(\frac{1251}{87}\)
Học tốt nhá :))
Bài làm :
\(a,17x+33x=100\)
\(\left(17+33\right)x=100\)
\(50x=100\)
\(x=2\)
\(b,23x+15\left(x+7\right)=105\)
\(23x+15x+105=105\)
\(38x=0\)
\(x=0\)
\(c,32\left(x-11\right)+4x=152\)
\(32x-352+4x=152\)
\(36x=504\)
\(x=14\)
\(d,51\left(3x+5\right)-406=22\left(3x+50\right)\)
\(153x+255-406=66x+1100\)
\(153x-66x=1100+406-255\)
\(87x=1251\)
\(x=\frac{1251}{87}\)
Học tốt
Bài 1 :
\(\frac{3n+2}{n+1}=\frac{3\left(x+1\right)-1}{n+1}=\frac{-1}{n+1}\)
=> n + 1 \(\in\)Ư(-1) = {1;-1}
Tự lập bảng xét giá trị bn nhé !
Bài 2 :
\(\frac{5}{x}-\frac{y}{3}=\frac{1}{6}\)
\(\Leftrightarrow\frac{5}{x}=\frac{1}{6}+\frac{y}{3}\)
\(\Leftrightarrow\frac{5}{x}=\frac{1+2y}{6}\)
\(\Leftrightarrow30=x\left(1+2y\right)\)
Tự lập bảng nhé !
Bài toán 1: Tính.
a) (-34) + (-91) + (-26) + (-99)
= [(-34) + (-26)] + [(-91) + (-99)]
= -60 + (-190)
= -250
b) 125 + |-25|
= 125 + 25
= 150
c) |-26| + |-34|
= 26 + 34
= 60
d) |-82| + (-120)
= -82 + (-120)
= -202
e) (-275) + |-115|
= -275 + 115
= -160
f) (-34) + |-34|
= (-34) + 34
= 0
a, \(21\in B\left(x-3\right)\Leftrightarrow x-3\inƯ\left(21\right)\Leftrightarrow x-3\in\left\{1;3;7;21;-1;-3;-7;-21\right\}\)
\(\Leftrightarrow x\in\left\{4;6;10;24;2;0;-4;-18\right\}\)
Vì \(x\in N\Rightarrow x\in\left\{4;6;10;24;2;0\right\}\)
b, \(1-x\inƯ\left(17\right)\Leftrightarrow1-x\in\left\{1;17;-1;-17\right\}\)
\(\Leftrightarrow x\in\left\{0;-16;2;18\right\}\)
Vì \(x\in N\Rightarrow x\in\left\{0;2;18\right\}\)
c, \(2x+3\in B\left(2x-1\right)\)
\(\Leftrightarrow2x+3⋮2x-1\Leftrightarrow2x-1+4⋮2x-1\Leftrightarrow4⋮2x-1\)
\(\Leftrightarrow2x-1\inƯ\left(4\right)\Leftrightarrow2x-1\in\left\{1;2;4;-1;-2;-4\right\}\)
\(\Leftrightarrow x\in\left\{1;\frac{3}{2};\frac{5}{2};0;\frac{-1}{2};\frac{-3}{2}\right\}\)
Vì \(x\in N\Rightarrow x\in\left\{1;0\right\}\)
d, \(x+1\inƯ\left(x^2+x+3\right)\Leftrightarrow x^2+x+3⋮x+1\Leftrightarrow x\left(x+1\right)+3⋮x+1\Leftrightarrow3⋮x+1\)
\(\Leftrightarrow x+1\inƯ\left(3\right)\Leftrightarrow x+1\in\left\{1;3;-1;-3\right\}\)
\(\Leftrightarrow x\in\left\{0;2;-2;-4\right\}\)
Vì \(x\in N\Rightarrow x\in\left\{0;2\right\}\)
\(a,2448:\left[119-\left(x-6\right)\right]=24\)
\(119-\left(x-6\right)=2448:24\)
\(119-\left(x-6\right)=102\)
\(x-6=119-102\)
\(x-6=17\)
\(x=17+6\)
\(\Rightarrow x=23\)
\(b,2016-100\times\left(x+11\right)=128:8\)
\(2016-100\times\left(x+11\right)=16\)
\(100\times\left(x+11\right)=2016-16\)
\(100\times\left(x+11\right)=2000\)
\(x+11=2000:100\)
\(x+11=20\)
\(x=20-11\)
\(\Rightarrow x=9\)
\(a,2448:\left[119-\left(x-6\right)\right]=24\\ 119-\left(x-6\right)=2448:24\\ 119-\left(x-6\right)=102\\ x-6=119-102\\ x-6=17\\ x=17+6\\ x=23\\ b,2016-100\times\left(x+11\right)=128:8\\ 2016-100\times\left(x+11\right)=16\\ 100\times\left(x+11\right)=2016-16\\ 100\times\left(x+11\right)=2000\\ x+11=2000:100\\ x+11=20\\ x=20-11\\ x=9\)