d: \(\frac{x}{6}-\frac{2}{y}=\frac{1}{30}\)

=>\(\frac{x}{6}-\frac{1}{30}=\frac{2}{y}\)

=>\(\frac{5x-1}{30}=\frac{2}{y}\)

=>\(y\left(5x-1\right)=60\)

=>(5x-1;y)∈{(1;60);(60;1);(-1;-60);(-60;-1);(2;30);(30;2);(-2;-30);(-30;-2);(3;20);(20;3);(-3;-20);(-20;-3);(4;15);(15;4);(-4;-15);(-15;-4);(5;12);(12;5);(-5;-12);(-12;-5);(6;10);(10;6);(-6;-10);(-10;-6)}

=>(5x;y)∈{(2;60);(61;1);(0;-60);(-59;-1);(3;30);(31;2);(-1;-30);(-29;-2);(4;20);(21;3);(-2;-20);(-19;-3);(5;15);(16;4);(-3;-15);(-14;-4);(6;12);(13;5);(-4;-12);(-11;-5);(7;10);(11;6);(-5;-10);(-9;-6)}

=>(x;y)∈{(2/5;60);(61/5;1);(0;-60);(-59/5;-1);(3/5;30);(31/5;2);(-1/5;-30);(-29/5;-2);(4/5;20);(21/5;3);(-2/5;-20);(-19/5;-3);(1;15);(16/5;4);(-3/5;-15);(-14/5;-4);(6/5;12);(13/5;5);(-4/5;-12);(-11/5;-5);(7/5;10);(11/5;6);(-1;-10);(-9/5;-6)}

c: \(\frac{5}{x}-\frac{y}{3}=\frac16\)

=>\(\frac{5}{x}=\frac{y}{3}+\frac16=\frac{2y+1}{6}\)

=>x(2y+1)=30

=>(x;2y+1)∈{(1;30);(30;1);(-1;-30);(-30;-1);(2;15);(15;2);(-2;-15);(-15;-2);(3;10);(10;3);(-3;-10);(-10;-3);(5;6);(6;5);(-5;-6);(-6;-5)}

=>(x;2y)∈{(1;29);(30;0);(-1;-31);(-30;-2);(2;14);(15;1);(-2;-16);(-15;-3);(3;9);(10;2);(-3;-11);(-10;-4);(5;5);(6;4);(-5;-7);(-6;-6)}

=>(x;y)∈{(1;29/2);(30;0);(-1;-31/2);(-30;-1);(2;7);(15;1/2);(-2;-8);(-15;-3/2);(3;9/2);(10;1);(-3;-11/2);(-10;-2);(5;5/2);(6;2);(-5;-7/2);(-6;-3)}

b: \(\frac{4}{x}+\frac{y}{3}=\frac56\)

=>\(\frac{4}{x}=\frac56-\frac{y}{3}=\frac{5-2y}{6}\)

=>x(5-2y)=24

=>x(2y-5)=-24

=>(x;2y-5)∈{(1;-24);(-24;1);(-1;24);(24;-1);(2;-12);(-12;2);(-2;12);(12;-2);(3;-8);(-8;3);(-3;8);(8;-3);(4;-6);(-6;4);(-4;6);(6;-4)}

=>(x;2y)∈{(1;-19);(-24;6);(-1;29);(24;4);(2;-7);(-12;7);(-2;17);(12;3);(3;-3);(-8;8);(-3;13);(8;2);(4;-1);(-6;9);(-4;11);(6;1)}

=>(x;y)∈{(1;-19/2);(-24;3);(-1;29/2);(24;2);(2;-7/2);(-12;7/2);(-2;17/2);(12;3/2);(3;-3/2);(-8;4);(-3;13/2);(8;1);(4;-1/2);(-6;9/2);(-4;11/2);(6;1/2)}

a: \(\frac{x}{3}-\frac{4}{y}=\frac15\)

=>\(\frac{x}{3}-\frac15=\frac{4}{y}\)

=>\(\frac{5x-3}{15}=\frac{4}{y}\)

=>y(5x-3)=60

=>(5x-3;y)∈{(1;60);(60;1);(-1;-60);(-60;-1);(2;30);(30;2);(-2;-30);(-30;-2);(3;20);(20;3);(-3;-20);(-20;-3);(4;15);(15;4);(-4;-15);(-15;-4);(5;12);(12;5);(-5;-12);(-12;-5);(6;10);(10;6);(-6;-10);(-10;-6)}

=>(5x;y)∈{(4;60);(63;1);(2;-60);(-57;-1);(5;30);(33;2);(1;-30);(-27;-2);(6;20);(23;3);(0;-20);(-17;-3);(7;15);(18;4);(-1;-15);(-12;-4);(8;12);(15;5);(-2;-12);(-9;-5);(9;10);(13;6);(-3;-10);(-7;-6)}

=>(x;y)∈{(4/5;60);(63/5;1);(2/5;-60);(-57/5;-1);(1;30);(33/5;2);(1/5;-30);(-27/5;-2);(6/5;20);(23/5;3);(0;-20);(-17/5;-3);(7/5;15);(18/5;4);(-1/5;-15);(-12/5;-4);(8/5;12);(3;5);(-2/5;-12);(-9/5;-5);(9/5;10);(13/5;6);(-3/5;-10);(-7/5;-6)}

x=6.5

ko có câu nào cả!

a) 

\(\Rightarrow\dfrac{47}{10}.x=\dfrac{1}{5}+\dfrac{2}{3}\)

\(\Rightarrow\dfrac{47}{10}.x=\dfrac{3}{15}+\dfrac{10}{15}\)

\(\Rightarrow\dfrac{47}{10}.x=\dfrac{13}{15}\)

\(\Rightarrow x=\dfrac{13}{15}:\dfrac{47}{10}\)

\(\Rightarrow x=\dfrac{13}{10}.\dfrac{10}{47}\)

\(\Rightarrow x=\dfrac{13}{47}\)

b)

\(\Rightarrow\dfrac{5}{7}:x=\dfrac{1}{6}-\dfrac{4}{5}\)

\(\Rightarrow\dfrac{5}{7}:x=\dfrac{5}{30}-\dfrac{24}{30}\)

\(\Rightarrow\dfrac{5}{7}:x=-\dfrac{19}{30}\)

\(\Rightarrow x=\dfrac{5}{7}:\left(-\dfrac{19}{30}\right)\)

\(\Rightarrow x=\dfrac{5}{7}.\left(-\dfrac{30}{19}\right)\)

\(\Rightarrow x=-\dfrac{150}{133}\)

a: \(\dfrac{-8}{3}\cdot\dfrac{15}{24}=\dfrac{-8}{24}\cdot\dfrac{15}{3}=\dfrac{-1}{3}\cdot5=-\dfrac{5}{3}\)

b: \(=\dfrac{3}{4}\cdot\dfrac{1}{-9}=\dfrac{-1}{12}\)

c: \(x=-\dfrac{7}{6}+\dfrac{5}{8}=-\dfrac{13}{24}\)

d: \(x=-\dfrac{14}{25}-\dfrac{3}{4}=\dfrac{-56-75}{100}=\dfrac{-131}{100}\)

a,1/4

b,8

a, 1/4
b,8

A)4/5x (5/6+1/6)

   4/5x     1= 4/5

\(a,\dfrac{5}{6}\times\dfrac{4}{5}+\dfrac{4}{5}\times\dfrac{1}{6}+\dfrac{4}{5}=\dfrac{4}{5}\times\left(\dfrac{5}{6}+\dfrac{1}{6}+1\right)=\dfrac{4}{5}\times2=\dfrac{8}{5}\)

\(b,60\times\left(\dfrac{105}{180}+\dfrac{48}{180}\right)=60\times\dfrac{17}{20}=51\)

a: 128-2x=-8-x

=>-2x+x=-8-128

=>-x=-136

=>x=136

b: \(x-\left(-15\right)\cdot2=55-7\cdot\left(-3\right)\)

=>x+30=55+21

=>x+30=76

=>x=76-30

=>x=46

c: \(66-\left\lbrack5-\left(-x\right)\right\rbrack=169\)

=>66-[5+x]=169

=>x+5=66-169=-103

=>x=-103-5

=>x=-108

d: (8-2x)(8+x)=0

=>2(4-x)(8+x)=0

=>(x-4)(x+8)=0

=>\(\left[\begin{array}{l}x-4=0\\ x+8=0\end{array}\right.\Rightarrow\left[\begin{array}{l}x=4\\ x=-8\end{array}\right.\)

e: \(7-\left\lbrack x^2+\left(-9\right)\right\rbrack=-20\)

=>\(x^2-9=7+20=27\)

=>\(x^2=36\)

=>\(\left[\begin{array}{l}x=6\\ x=-6\end{array}\right.\)

bài 2 tìm x

a,106- ( x+ 7) =9

x+7 = 106 - 9

x+7 = 107

x= 107 - 7

x=100

b, 2 x ( x+ 4) + 5 =65

2 x (x+4) = 65 - 5

2 x (x+4) = 60

x+4 = 60:2

x+4= 30

x= 30 - 4

x=26

c, (16x x -32) x 45=0

16 x X - 32 = 0: 45

16 x X - 32 =0

16 x X = 0 + 32

16 x X = 32

X= 32:16

X=2

d, x+4 x x = 100 : 5

X + 4 x X = 20

(1+4) x X = 20

5 x X  = 20

X= 20:5

X=4

ủa bài 1 đâu =]]

Chọn B