Tìm x :
5 / 7 + x / 35 = 4 / 5
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\(\dfrac{5}{7}+\dfrac{x}{35}=\dfrac{4}{5}\)
\(\dfrac{x}{35}=\dfrac{4}{5}-\dfrac{5}{7}\)
\(\dfrac{x}{35}=\dfrac{28}{35}-\dfrac{25}{35}\)
\(\dfrac{x}{35}=\dfrac{3}{35}\)
\(x=3\)
#Sahara |
a: =>x=3/7+3/5=15/35+21/35=36/35
b: =>x/35=4/5-5/7=28/35-25/35=3/35
=>x=3
c: =>x<3/4+8/4=11/4
=>\(x\in\left\{0;1;2;3\right\}\)
d: =>5/3<x<5/6+24/6=29/6
=>\(x\in\left\{2;3;4\right\}\)
e: =>x<10/12-9/12=1/12
=>x=0
f: =>2/3<x<12/6-5/6=7/6
=>x=1
a, ta thấy cả hai vế đều có 4/5 mà lại bằng nhau nên x bằng số hạng còn lại ở vế phải
x=3/7+3/5
x=36/35
b,x là số hạng chưa biết nên
x=4/5-5/7
x=3/35
a: =>x+7/4=6:2/3=9
=>x=29/4
b: =>x:5/3=7/5
=>x=7/5*5/3=7/3
c:=>x+1/6=5/3
=>x=10/6-1/6=3/2
d: =>x+4/5=4/5+3/7+3/5
=>x=3/7+3/5=36/35
e: =>x/35=4/5-5/7=3/35
=>x=3
f: =>13/28+x=1/2
=>x=1/28
g: =>1/3-x=1/9
=>x=2/9
\(\dfrac{3}{7}\times x=\dfrac{1}{3}\)
\(x=\dfrac{1}{3}:\dfrac{3}{7}\)
\(x=\dfrac{7}{9}\)
\(x:\dfrac{6}{8}=\dfrac{2}{5}\)
\(x=\dfrac{2}{5}\times\dfrac{6}{8}\)
\(x=\dfrac{6}{20}=\dfrac{3}{10}\)
\(x-\dfrac{2}{3}=\dfrac{5}{6}\)
\(x=\dfrac{5}{6}+\dfrac{2}{3}\)
\(x=\dfrac{9}{6}=\dfrac{3}{2}\)
\(x-\dfrac{2}{5}-\dfrac{4}{35}=\dfrac{1}{7}\)
\(x=\dfrac{1}{7}+\dfrac{4}{35}+\dfrac{2}{5}\)
\(x=\dfrac{23}{35}\)
.
a. (5.x + 3) : 4 – 16 = 6
(5.x + 3) : 4 = 22
(5.x + 3) = 88
5.x = 85
x = 13
b. 7(23 – 3.x) : 2 – 35 = 35
7(23 – 3.x) : 2 = 70
7(23 – 3.x) = 35
7 . 3.x = 12
7.x = 4
x = 4/7
a.) (5.x + 3) : 4 – 16 = 6
=> (5.x + 3) : 4 = 22
=> 5.x + 3 = 88
=> 5x = 85
=> x = 17
b) 7(23 – 3.x) : 2 – 35 = 35
=> 7(23 – 3.x) : 2 = 70
=>7(23 – 3.x) = 140
=> 23 – 3.x = 20
=> 3x = 3
=> x = 1
a: =>5-x=-23
=>x=5+23=28
b: =>x-3-x+7-25+x=54
=>x-21=54
=>x=75
c: =>7-9x-2x+4=-5x-35+27-25=-5x-37
=>-11x+3=-5x-37
=>-6x=-40
=>x=20/3
a.
10-x-5 = (-5) - 7 -11
=>5-x = 0
=>x=5
b
(x-3) - (x+17-24) - (25-x) = 24 - (-30)
=>x - 3 - x - 17 + 24 - 25 - x = 24 + 30
=>-x - 21 = 54
=>-x = 75
=>x = -75
c
(7 - 9x) - (2x - 4) = - (5x + 35) - (-27) - 25
=>7-9x - 2x + 4 = -5x - 35 + 27 - 35
=>11 - 11x + 5x = -43
=>16x = 11 + 43
=>16x = 54
=>x=4
Bài 1:
a) Ta có: \(\dfrac{17}{6}-x\left(x-\dfrac{7}{6}\right)=\dfrac{7}{4}\)
\(\Leftrightarrow\dfrac{17}{6}-x^2+\dfrac{7}{6}x-\dfrac{7}{4}=0\)
\(\Leftrightarrow-x^2+\dfrac{7}{6}x+\dfrac{13}{12}=0\)
\(\Leftrightarrow-12x^2+14x+13=0\)
\(\Delta=14^2-4\cdot\left(-12\right)\cdot13=196+624=820\)
Vì Δ>0 nên phương trình có hai nghiệm phân biệt là:
\(\left\{{}\begin{matrix}x_1=\dfrac{14-2\sqrt{205}}{-24}=\dfrac{-7+\sqrt{205}}{12}\\x_2=\dfrac{14+2\sqrt{2015}}{-24}=\dfrac{-7-\sqrt{205}}{12}\end{matrix}\right.\)
b) Ta có: \(\dfrac{3}{35}-\left(\dfrac{3}{5}-x\right)=\dfrac{2}{7}\)
\(\Leftrightarrow\dfrac{3}{5}-x=\dfrac{3}{35}-\dfrac{10}{35}=\dfrac{-7}{35}=\dfrac{-1}{5}\)
hay \(x=\dfrac{3}{5}-\dfrac{-1}{5}=\dfrac{3}{5}+\dfrac{1}{5}=\dfrac{4}{5}\)
\(\frac{5}{7}+\frac{x}{35}=\frac{4}{5}\)
\(\Rightarrow\frac{x}{35}=\frac{4}{5}-\frac{5}{7}\)
\(\Rightarrow\frac{x}{35}=\frac{28-25}{35}\)
\(\Rightarrow\frac{x}{35}=\frac{3}{35}\)
\(\Rightarrow x=3\)
Vậy x = 3
\(\frac{5}{7}+\frac{x}{35}=\frac{4}{5}\)
\(\frac{x}{35}=\frac{4}{5}-\frac{5}{7}\)
\(\frac{x}{35}=\frac{28}{35}-\frac{25}{35}\)
\(\Rightarrow x=3\)
\(\frac{x}{35}=\frac{3}{5}\)