Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
A) 2/3 - x - 1/5 = 2/5 - 1/7
2/3 - x - 1/5 = 9/35
2/3 - x = 9/35 + 1/5
2/3 - x = 16/35
x = 2/3 - 16/35 = 22/105
B) 1/2 x X : 2/3 = 1 2/5
1/2 x X : 2/3 = 7/5
1/2 x X = 7/5 x 2/3
1/2 x X = 14/15
X =14/15 : 1/2
X = 28/15
C) 2/5 x X + X x 1/5 = 2/7
X x ( 2/5 + 1/5 ) = 2/7
X x 3/5 = 2/7
X = 2/7 : 3/5 = 10/21
\(x-\dfrac{11}{15}=3+\dfrac{x}{5}\\ \Leftrightarrow\dfrac{4}{5}x=\dfrac{56}{15}\\ \Leftrightarrow x=\dfrac{14}{3}\)
\(\dfrac{2}{5}\times\dfrac{1}{x}+\dfrac{1}{x}\times2+\dfrac{2}{5}=\dfrac{1}{2}\\ \Leftrightarrow\dfrac{12}{5}\times\dfrac{1}{x}=\dfrac{1}{10}\\ \Leftrightarrow\dfrac{1}{x}=\dfrac{1}{24}\\ \Leftrightarrow x=24\)
a: =>7/9:x=1/18-2/9=1/18-4/18=-3/18=-1/6
=>x=-7/9:1/6=-7/9*6=-42/9=-14/3
b: =>x*7/5=2/15+2/5=8/15
=>x=8/15:7/5=8/21
c: =>x-1/2=3/14:4/7=3/8
=>x=3/8+4/8=7/8
d: =>0,4x+0,3x-0,2x=0,7
=>0,5x=0,7
=>x=1,4
\(\frac{2}{5}\cdot\frac{1}{2}-\frac{2}{5}\cdot\frac{1}{3}-\frac{2}{5}\cdot\frac{1}{6}\)
\(=\frac{2}{5}\cdot\left(\frac{1}{2}-\frac{1}{3}-\frac{1}{6}\right)\)
\(=\frac{2}{5}\cdot\frac{0}{6}=\frac{2}{5}\cdot0=0\)
tìm x
a) \(0,5+\left(x-\frac{15}{2}\right):\frac{1}{2}=\frac{9}{2}\)
\(\Rightarrow x=\frac{19}{2}=8,5\)
b) \(2012\cdot x-2010\cdot x=2014\)
\(\Leftrightarrow\left(2012-1010\right)\cdot x=2014\)
\(\Leftrightarrow2x=2014\)
\(\Rightarrow x=\frac{2014}{2}=1007\)
hok tốt .
Tính nhanh:
2/5 x 1/2 - 2/5 x 1/3 - 2/5 x 1/6
= 2/5 x ( 1/2 - 1/3 - 1/6 )
= 2/5 x ( 3/6 - 2/6 - 1/6 )
= 2/5 x 0/6
=0
Bài 1
a) 3 2/5 - 1/2
= 17/5 - 1/2
= 34/10 - 5/10
= 29/10
b) 4/5 + 1/5 × 3/4
= 4/5 + 3/20
= 16/20 + 3/20
= 19/20
c) 3 1/2 × 1 1/7
= 7/2 × 8/7
= 4
d) 4 1/6 : 2 1/3
= 25/6 : 7/3
= 25/14
Bài 2
a) 3 × 1/2 + 1/4 × 1/3
= 3/2 + 1/12
= 18/12 + 1/12
= 19/12
b) 1 4/5 - 2/3 : 2 1/3
= 9/5 - 2/3 : 7/3
= 9/5 - 2/7
= 63/35 - 10/35
= 53/35
\(6-2\left(x-1\right)=4\)
\(\Rightarrow2\left(x-1\right)=6-4\)
\(\Rightarrow2\left(x-1\right)=2\)
\(\Rightarrow x-1=1\)
\(\Rightarrow x=1+1=2\)
________________
\(2\cdot\left(x-2\right)+1=7\)
\(\Rightarrow2\cdot\left(x-2\right)=7-1\)
\(\Rightarrow2\cdot\left(x-2\right)=6\)
\(\Rightarrow x-2=3\)
\(\Rightarrow x=3+2=5\)
_______________
\(\left(2\cdot x-3\right)+4=9\)
\(\Rightarrow2\cdot x-3=5\)
\(\Rightarrow2\cdot x=3+5\)
\(\Rightarrow2\cdot x=8\)
\(\Rightarrow x=\dfrac{8}{2}=4\)
________________
\(\left(3\cdot x-2\right)-1=3\)
\(\Rightarrow3\cdot x-2=3+1\)
\(\Rightarrow3\cdot x-2=4\)
\(\Rightarrow3\cdot x=6\)
\(\Rightarrow x=\dfrac{6}{3}=2\)
a: =>2(x-1)=2
=>x-1=1
=>x=2
b: =>2(x-2)=6
=>x-2=3
=>x=5
c; =>2x-3=5
=>2x=8
=>x=4
d: =>3x-2=4
=>3x=6
=>x=2
e: =>2(6-x)=4
=>6-x=2
=>x=4
f: =>x-2=5
=>x=7
g: =>10-2x=4
=>2x=6
=>x=3
h: =>2x+4=3
=>2x=-1
=>x=-1/2
j: =>x+2=12
=>x=10
l: =>2x+3=3
=>2x=0
=>x=0
\(x:2\frac{1}{2}\times x+2\frac{1}{5}=5\frac{1}{2}\)
\(x:\frac{5}{2}\times x+\frac{11}{5}=\frac{11}{2}\)
\(x\times\frac{2}{5}\times x+\frac{11}{5}=\frac{11}{2}\)
\(x\times x\times\frac{2}{5}=\frac{11}{2}-\frac{11}{5}\)
\(x\times x\times\frac{2}{5}=\frac{33}{10}\)
\(x\times x=\frac{33}{10}:\frac{2}{5}\)
\(x\times x=\frac{33}{4}\)
\(\Rightarrow x=\sqrt{\frac{33}{4}}\)
\(x=2,8722...\)
CHÚC BN HỌC TỐT!!!!!