a: \(y\times4\frac{7}{12}=6\frac14\)

=>\(y\times\frac{55}{12}=\frac{25}{4}\)

=>\(y=\frac{25}{4}:\frac{55}{12}=\frac{25}{4}\times\frac{12}{55}=\frac{3\times5}{11}=\frac{15}{11}\)

b: \(y:3\frac78=5\frac12\)

=>\(y:\frac{31}{8}=\frac{11}{2}\)

=>\(y=\frac{11}{2}\times\frac{31}{8}=\frac{341}{16}\)

c: \(6\frac17:y=5\frac25\)

=>\(\frac{43}{7}:y=\frac{27}{5}\)

=>\(y=\frac{43}{7}:\frac{27}{5}=\frac{43}{7}\times\frac{5}{27}=\frac{215}{189}\)

a, \(y=\dfrac{7}{11}-\dfrac{5}{14}=\dfrac{98-55}{154}=\dfrac{43}{154}\)

b, \(y=\dfrac{8}{9}.\dfrac{4}{7}=\dfrac{32}{63}\)

a) 3/4*41/24=41/32

B)  y=4/7:3/5

y=20/21

a)3/4 × (5/6 + 7/8)

=3/4 × 41/24

=41/32

b)3/5 × y=4/7

  y=4/7:3/5

          y=20/21

a) 3/5+y=9/8

y= 21/40

b) 13/5-y= 1/8

y=99/40

cậu viết cách làm được ko?

5 x y - 7 = 8 + 2 x y 

5 x y - 7 - 2 x y = 8

( 5 x y - 2 x y  ) - 7 = 8

3 x y - 7 = 8

3 x y = 8 + 7

3 x y = 15

y = 15 : 3

y = 5

Vậy ...

\(5\times y-7=8+2\times y\)

\(5\times y-7-2\times y=8\)

\(\left(5\times y-2\times y\right)-7=8\)

\(3\times y-7=8\)

\(3\times y=8+7\)

\(3\times y=15\)

          \(y=15\div3\)

          \(y=5\)

`7/2 : y= 3/8 + 5/4`

`=> 7/2 : y= 3/8 +10/8`

`=> 7/2 : y=13/8`

`=> y= 7/2 : 13/8`

`=> y= 7/2 xx 8/13`

`=> y= 28/13`

\(\dfrac{7}{2}:y=\dfrac{3}{8}+\dfrac{5}{4}\)
\(\dfrac{7}{2}:y=\dfrac{13}{8}\)
\(y=\dfrac{7}{2}:\dfrac{13}{8}\)
\(y=\dfrac{7}{2}\times\dfrac{8}{13}\)
\(y=\dfrac{28}{13}\)

\(\frac{4}{7}+y=\frac{5}{8}-\frac{1}{4}\)

\(\frac{4}{7}+y=\frac{3}{8}\)

           \(y=\frac{3}{8}-\frac{4}{7}\)

           \(y=-\frac{11}{56}\)

hình như bạn ra sai đề rồi

\(\frac{4}{7}+y=\frac{3}{8}\)

\(y=\frac{3}{8}-\frac{4}{7}=-\frac{11}{56}\)

a)

y : 5 + 27 = 4 × 8

y : 5 + 27 = 32

y : 5 = 32 – 27

y : 5 = 5

y = 5 × 5

y = 25

b)

12 – 7 < y < 12 – 4

5 < y < 8

y = 6; 7

a: Để y là số nguyên thì 4x-8⋮2x+5

=>4x+10-18⋮2x+5

=>-18⋮2x+5

mà 2x+5 lẻ

nên 2x+5∈{1;-1;3;-3;9;-9}

=>2x∈{-4;-6;-2;-8;4;-14}

=>x∈{-2;-3;-1;-4;2;-7}

\(y=\frac{4x-8}{2x+5}=\frac{4x+10-18}{2x+5}=2-\frac{18}{2x+5}\)

Khi x=-2 thì \(y=2-\frac{18}{2x+5}=2-\frac{18}{2\cdot\left(-2\right)+5}=2-\frac{18}{1}=2-18=-16\)

Khi x=-3 thì \(y=2-\frac{18}{2x+5}=2-\frac{18}{2\cdot\left(-3\right)+5}=2-\frac{18}{-1}=2+18=20\)

Khi x=-1 thì \(y=2-\frac{18}{2x+5}=2-\frac{18}{2\cdot\left(-1\right)+5}=2-\frac{18}{3}=2-6=-4\)

Khi x=-4 thì \(y=2-\frac{18}{2x+5}=2-\frac{18}{2\cdot\left(-4\right)+5}=2-\frac{18}{-3}=2+6=8\)

Khi x=2 thì \(y=2-\frac{18}{2x+5}=2-\frac{18}{2\cdot2+5}=2-\frac{18}{9}=2-2=0\)

Khi x=-7 thì \(y=2-\frac{18}{2x+5}=2-\frac{18}{2\cdot\left(-7\right)+5}=2-\frac{18}{-9}=2+2=4\)

b: xy-3x+2y=7

=>x(y-3)+2y-6=1

=>(x+2)(y-3)=1

=>(x+2;y-3)∈{(1;1);(-1;-1)}

=>(x;y)∈{(-1;4);(-3;2)}