Tìm y.
4 < y ÷ 7 < 8.
tìm y:
a/ 7/11 - y = 5/14 b/ y : 4/7 = 8/9
a, \(y=\dfrac{7}{11}-\dfrac{5}{14}=\dfrac{98-55}{154}=\dfrac{43}{154}\)
b, \(y=\dfrac{8}{9}.\dfrac{4}{7}=\dfrac{32}{63}\)
4/7+y=5/8-1/4 Tìm y
\(\frac{4}{7}+y=\frac{5}{8}-\frac{1}{4}\)
\(\frac{4}{7}+y=\frac{3}{8}\)
\(y=\frac{3}{8}-\frac{4}{7}\)
\(y=-\frac{11}{56}\)
hình như bạn ra sai đề rồi
\(\frac{4}{7}+y=\frac{3}{8}\)
\(y=\frac{3}{8}-\frac{4}{7}=-\frac{11}{56}\)
\(\frac{4}{7}+y=\frac{5}{8}-\frac{1}{4}\)
\(\frac{4}{7}+y=\frac{5}{8}-\frac{2}{8}\)
\(\frac{4}{7}+y=\frac{3}{8}\)
\(y=\frac{3}{8}-\frac{4}{7}\)
\(y=\frac{21}{56}-\frac{32}{56}\)
\(y=-\frac{11}{56}\)
Tìm y, biết:
a) y : 5 + 27 = 4 × 8
b) 12 – 7 < y < 12 – 4
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) Tính:
3/4 × (5/6 + 7/8)
b) Tìm y:
3/5 x y = 4/7
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
Câu 8 (1 điểm): Tìm y
3/5+ y =7/8 + 1/4 13/5 - y = 1/4 : 2
a) 3/5+y=9/8
y= 21/40
b) 13/5-y= 1/8
y=99/40
3/5+ y =7/8 + 1/4
y= 7/8 + 1/4 -3/5
y= 35/40 + 10/40 - 24/40
y=(35+10-24)/40
y=21/40
-------------------------------------------------------
13/5 - y = 1/4 : 2
y = 13/5 - 1/4 x 1/2
y = 13/5 - 1/8
y = 104/40 -5/40
y = 99/40
a) 3/5+y=9/8
y= 21/40
b) 13/5-y= 1/8
y=99/40
1.Tìm y
a, y x 4 7/12 = 6 1/4
b, y : 3 7/8 = 5 1/2
c, 6 1/7 : y = 5 2/5
Bài 1 : Tìm x,y thuộc Z :
1,( x + 1 ) . ( y - 2 ) = 0
2,( x - 5 ) . ( y - 7 ) = 1
3,( x + 4 ) . ( y - 2 ) = 2
4,( x - 4 ) . ( y + 3 ) = -3
5,( x + 3 ) . ( y - 6 ) = -4
6,( x - 8 ) . ( y + 7 ) = 5
7,( x + 7 ) . ( y - 3 ) = -6
8,( x - 6 ) . ( y + 2 ) = 7
1)\(\left(x+1\right).\left(y-2\right)=0\) \(\left(x,y\inℤ\right)\)
\(\Rightarrow\orbr{\begin{cases}x+1=0\\y-2=0\end{cases}}\Rightarrow\orbr{\begin{cases}x=-1\\y=2\end{cases}}\)
2)\(\left(x-5\right).\left(y-7\right)=1\)
x-5 | 1 | -1 |
y-7 | 1 | -1 |
x | 6 | 4 |
y | 8 | 6 |
3)\(\left(x+4\right).\left(y-2\right)=2\)
x+4 | 1 | 2 | -1 | -2 |
y-2 | 2 | 1 | -2 | -1 |
x | -3 | -2 | -5 | -6 |
y | 4 | 3 | 0 | 1 |
4)\(\left(x-4\right).\left(y+3\right)=-3\)
x-4 | 1 | -1 | 3 | -3 |
y+3 | -3 | 3 | -1 | 1 |
x | 5 | 3 | 7 | 1 |
y | -6 | 0 | -4 | -2 |
5)\(\left(x+3\right).\left(y-6\right)=-4\)
x+3 | -1 | 1 | -4 | 4 | 2 | -2 |
y-6 | 4 | -4 | 1 | -1 | -2 | 2 |
x | -4 | -2 | -7 | 1 | -1 | -5 |
y | 10 | 2 | 7 | 5 | 4 | 8 |
6)\(\left(x-8\right).\left(y+7\right)=5\)
x-8 | 1 | 5 | -1 | -5 |
y+7 | 5 | 1 | -5 | -1 |
x | 9 | 13 | 7 | 3 |
y | -2 | -6 | -12 | -8 |
7)\(\left(x+7\right).\left(y-3\right)=-6\)
x+7 | -1 | 1 | -6 | 6 | -2 | 2 | -3 | 3 |
y-3 | 6 | -6 | 1 | -1 | 3 | -3 | 2 | -2 |
x | -8 | -6 | -13 | -1 | -9 | -5 | -10 | -4 |
y | 9 | -3 | 4 | 2 | 6 | 0 | 5 | 1 |
8)\(\left(x-6\right).\left(y+2\right)=7\)
x-6 | 1 | 7 | -1 | -7 |
y+2 | 7 | 1 | -7 | -1 |
x | 7 | 13 | 5 | -1 |
y | 5 | -1 | -9 | -3 |
ok :)
tìm y ,biết : \(\dfrac{7}{2}\): y = \(\dfrac{3}{8}\) + \(\dfrac{5}{4}\)
y =
`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`
\(\dfrac{7}{2}:y=\dfrac{3}{8}+\dfrac{5}{4}\)
\(\dfrac{7}{2}:y=\dfrac{13}{8}\)
\(y=\dfrac{7}{2}:\dfrac{13}{8}\)
\(y=\dfrac{7}{2}\times\dfrac{8}{13}\)
\(y=\dfrac{28}{13}\)
1: Áp dụng tính chất của DTSBN, ta được:
\(\dfrac{x}{7}=\dfrac{y}{13}=\dfrac{x-y}{7-13}=\dfrac{42}{-6}=-7\)
=>x=-48; y=-91
2: x/y=3/4
=>4x=3y
=>4x-3y=0
mà 2x+y=10
nên x=3 và y=4
3: =>7x-3y=0 và x-y=-24
=>x=18 và y=42
4: =>7x-5y=0 và x+y=24
=>x=10 và y=14