Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
Rút gọn: \(\frac{56}{49}=\frac{8}{7}\)
\(\frac{y}{7}=\frac{8}{7}\Rightarrow y=8\)
Rút gọn: \(\frac{15}{27}=\frac{5}{9}\)
\(\frac{5}{9}=\frac{5}{y}\Rightarrow y=9\)
a) y/7=56/49=> 7.56=y.49
=> y=7.56:49
=>y=8 vậy y=8
b)15/49=5/y
=> 15y=27.5
=> y=27.5:15
=>y=9 vậy y=9
tìm y
a)y 56 b) 15 5
__ = __ __ = __
7 49 27 y
\(a,\Rightarrow7y=56\Leftrightarrow y=8\)
b, \(\Rightarrow3y=27\Leftrightarrow y=9\)
a) y.49 = 56.7
y.49=392
y=392:49
y=8
b)15.y=27.5
15.y= 135
y=135:15
y=9
(tick nhé)
\(12:y=\frac{3}{4}+\frac{4}{5}\)
\(12:y=\frac{15}{20}+\frac{16}{20}\)
\(12:y=\frac{31}{20}\)
\(y=12:\frac{31}{20}\)
\(y=12x\frac{20}{31}\)
\(y=\frac{240}{31}\)
\(\frac{4}{5}xY=1\)
\(y=1:\frac{4}{5}\)
\(y=1x\frac{5}{4}\)
\(y=\frac{5}{4}\)
\(\frac{37}{63}-y=\frac{1}{7}\)
\(y=\frac{37}{63}-\frac{1}{7}\)
\(y=\frac{37}{63}-\frac{9}{63}\)
\(y=\frac{28}{63}\)
\(y=\frac{4}{9}\)
\(y:\frac{3}{7}=\frac{3}{42}+\frac{5}{7}\)
\(y:\frac{3}{7}=\frac{3}{42}+\frac{30}{42}\)
\(y:\frac{3}{7}=\frac{33}{42}\)
\(y:\frac{3}{7}=\frac{11}{14}\)
\(y=\frac{11}{14}x\frac{3}{7}\)
\(y=\frac{33}{98}\)
\(12:y=\frac{3}{4}+\frac{4}{5}\) \(\frac{37}{63}-y=\frac{1}{7}\)
\(12:y=\frac{31}{20}\) \(y=\frac{37}{63}-\frac{1}{7}\)
\(y=12:\frac{31}{20}\) \(y=\frac{4}{9}\)
\(y=\frac{240}{31}\)
\(\frac{4}{5}\cdot y=1\) \(y:\frac{3}{7}=\frac{3}{42}+\frac{5}{7}\)
\(y=1:\frac{4}{5}\) \(y:\frac{3}{7}=\frac{11}{14}\)
\(y=\frac{5}{4}\) \(y=\frac{11}{14}.\frac{3}{7}\)
\(y=\frac{33}{98}\)
\(\dfrac{1}{5}+y=7\)
\(y=7-\dfrac{1}{5}\)
\(y=\dfrac{35}{5}-\dfrac{1}{5}\)
\(y=\dfrac{34}{5}\)
_________________________
\(y:\dfrac{3}{4}=\dfrac{5}{7}\)
\(y=\dfrac{5}{7}\times\dfrac{3}{4}\)
\(y=\dfrac{15}{28}\)
Chúc bạn học tốt
Tìm các số tự nhiên x và y biết : 4/x = y/21=28/49
\(\dfrac{4}{x}=\dfrac{y}{21}=\dfrac{28}{49}\\ \Rightarrow\dfrac{4}{x}=\dfrac{y}{21}=\dfrac{4}{7}\)
\(\dfrac{4}{x}=\dfrac{4}{7}\Rightarrow x=7\)
\(\dfrac{y}{21}=\dfrac{4}{7}\Rightarrow\dfrac{y}{21}=\dfrac{12}{21}\Rightarrow y=12\)
a) y × 2/5 + y × 3/5 = 5/7
y x ( 2/5 + 3/5) = 5/7
y x 5/5 = 5/7
y x 1 = 5/7
y = 5/7 : 1
y = 5/7
b) y × 7/2 - y × 3/2 = 3/4
y x ( 7/2 - 3/2) = 3/4
y x 4/2 = 3/4
y x 2 = 3/4
y = 3/4 : 2
y = 3/4 x 1/2
y = 3/8
`a,yxx(2/5+3/5)=5/7`
`y xx1=5/7`
`y=5/7:1`
`y=5/7`
`b,y xx(7/2-3/2)=3/4`
`y xx2=3/4`
`y =3/4:2`
`y=3/2`
vì 4/x=28/49 nên x.28=4.49=196 ( dấu . là dấu nhân , vì sao x.28=4.49 cấp 2 học )
x=196:28=7
vì y/21=28/49 nên y.49=21.28=588
y=588:49=12
\(\frac{4}{x}=\frac{y}{21}=\frac{28}{49}\)
\(\Rightarrow\frac{4}{x}=\frac{12}{21}=\frac{28}{49}\)
\(\Rightarrow\frac{4}{7}=\frac{12}{21}=\frac{28}{49}\)
Vậy x = 7 , y = 12
Cách làm:
y = \(\frac{28\times21}{49}=12\)
x = \(\frac{21\times4}{12}=7\)
Công thức : nhân chéo
#Hok tốt !
(y+1)+(y+4)+...+(y+49)=442
(y+y+...+y)+(1+4+...+49)=442
17y+425=442
17y=442-425
17y=17
y=17/17
y=1
Vậy y=1
Theo đề ta có : ( 1 + 4 + 7 + 10 +.... + 49 ) + 17y = 442
415 + 17y = 442 .
17 y = 442 - 415
17y = 27