Bài 1 Tìm X
X+X×1/2:2/9+X:2/7=252
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
1: =>x^2+4x-21=0
=>(x+7)(x-3)=0
=>x=3 hoặc x=-7
2: =>(2x-5-4)(2x-5+4)=0
=>(2x-9)(2x-1)=0
=>x=9/2 hoặc x=1/2
3: =>x^3-9x^2+27x-27-x^3+27+9(x^2+2x+1)=15
=>-9x^2+27x+9x^2+18x+9=15
=>18x=15-9-27=-21
=>x=-7/6
6: =>4x^2+4x+1-4x^2-16x-16=9
=>-12x-15=9
=>-12x=24
=>x=-2
7: =>x^2+6x+9-x^2-4x+32=1
=>2x+41=1
=>2x=-40
=>x=-20
Bài 1:
a: x/-2=-18/x
=>x2=36
=>x=6 hoặc x=-6
b: x/2+x/5=17/10
=>7/10x=17/10
hay x=17/7
y+y x 1/3 : 2/9 + y :2/7 = 252
y x 1 + y x (1/3 x 9/2 ) + y x 7/2 = 252
y x 1/1 + y x 3/2 + y x 7/2 = 252
y x (1/1 + 3/2 + 7/2 ) = 252
y x 6 = 252
y = 252 : 6
y = 42
Bài 1:
Ta có: \(x-35\%\cdot x=\dfrac{1}{25}\)
\(\Leftrightarrow65\%\cdot x=\dfrac{1}{25}\)
\(\Leftrightarrow x=\dfrac{1}{25}:\dfrac{13}{20}=\dfrac{1}{25}\cdot\dfrac{20}{13}=\dfrac{4}{65}\)
Vậy: \(x=\dfrac{4}{65}\)
Bài 2:
a) Ta có: \(17\dfrac{2}{31}-\left(\dfrac{15}{17}+6\dfrac{2}{31}\right)\)
\(=17\dfrac{2}{31}-\dfrac{15}{17}-6\dfrac{2}{31}\)
\(=11+\dfrac{2}{31}-\dfrac{15}{17}\)
\(=\dfrac{5366}{527}\)
a)\(\frac{5}{9}\times x-1=\frac{8}{9}\)
\(\frac{5}{9}\times x=\frac{8}{9}+1\)
\(\frac{5}{9}\times x=\frac{17}{9}\)
\(x=\frac{17}{9}:\frac{5}{9}\)
\(x=\frac{17}{5}\)
1: Thay \(x=\dfrac{1}{25}\) vào C, ta được:
\(C=\left(\dfrac{1}{5}+2\right):\left(\dfrac{1}{5}-3\right)=\dfrac{11}{5}:\dfrac{-14}{5}=-\dfrac{11}{14}\)
2: Để C=-2 thì \(\sqrt{x}+2=-2\left(\sqrt{x}-3\right)\)
\(\Leftrightarrow\sqrt{x}+2+2\sqrt{x}-6=0\)
\(\Leftrightarrow3\sqrt{x}=4\)
hay \(x=\dfrac{16}{9}\)
Để \(C=\dfrac{7}{5}\) thì \(\dfrac{\sqrt{x}+2}{\sqrt{x}-3}=\dfrac{7}{5}\)
\(\Leftrightarrow7\sqrt{x}-21=2\sqrt{x}+10\)
\(\Leftrightarrow5\sqrt{x}=31\)
hay \(x=\dfrac{961}{25}\)
x+x*\(\frac{1}{2}\):\(\frac{2}{9}\)+x:\(\frac{2}{7}\)=252
x+x*\(\frac{9}{4}\)+x*\(\frac{7}{2}\)=252
x*(1+\(\frac{9}{4}\)+\(\frac{7}{2}\))=252
x*\(\frac{27}{4}\)=252
x=252:\(\frac{27}{4}\)
x=\(\frac{112}{3}\)
Vậy x=\(\frac{112}{3}\)
Học tốt
\(x+x\times\frac{1}{2}\div\frac{2}{9}+x\div\frac{2}{7}=252\)
\(x\times1+x\times\frac{9}{4}+x\times\frac{7}{2}=252\)
\(x\times\left(1+\frac{9}{4}+\frac{7}{2}\right)=252\)
\(x\times\frac{17}{4}=252\)
\(x=252\div\frac{17}{4}\)
\(x=252\times\frac{4}{17}\)
\(x=\frac{1008}{17}\)
Chắc sai =]]