Tìm x biết 42:x + 36:x=13
Tìm số nguyên x, biết: a) 4/6 = 16/x b) -5/14 = x/42 c) x/11 = -36/132 d) 5/x+2 = 13/39
a: \(\Leftrightarrow x=\dfrac{16\cdot6}{4}=24\)
b: \(\Leftrightarrow x=\dfrac{-5\cdot42}{14}=-15\)
c: \(\Leftrightarrow\dfrac{x}{11}=\dfrac{-3}{11}\)
hay x=-3
tìm x biết
11/13 - ( 5/42 - x ) = - ( 15 - 11/13 )
11/12-(5/42-x)=-(15-11/13)
=>11/13-(5/42-x)=184/13
=>5/42-x=11/13- (-184/13)
=>5/42-x=15
=>x=5/42-15
=>x=-625/42
5/42-x=11/13- [-(15-11/13)]=11/13+15-11/13
5/42-x=(11/13-11/13)+15=15
x=5/42-15=5/42-630/42
x=-625/42
Vậy x=-625/42
a, 36 - \(x\) = 42
\(x\) = 36 - 42
\(x\) = -6
b, 10 + 2\(x\) = 6
2\(x\) = 10 - 6
2\(x\) = 4
\(x\) = 2
20 \(⋮\) \(x\)
\(x\in\) Ư(20) = { -20; -10; -5; -4; -2; -1; 1; 2; 4; 5; 10; 20}
Vì - 5 ≤ \(x\) < 5
nên \(x\) \(\in\) {-5;- 4; -2; -1; 1; 2; 4; 5}
Tìm x biết : 200 - 18 : ( 42:3*x - 13 ) - 28 = 154
Lời giải:
$200-18:(42:3\times x-13)-28=154$
$200-28-18:(42:3\times x-13)=154$
$172-18:(42:3\times x-13)=154$
$18:(42:3\times x-13)=172-154=18$
$42:3\times x-13=18:18=1$
$14\times x-13=1$
$14\times x=13+1=14$
$x=14:14=1$
\(200-18:\left(42:3\times x-13\right)-28=154\)
\(200-18:\left(42:3\times x-13\right)=182\)
\(18:\left(42:3\times x-13\right)=200-182\)
\(18:\left(42:3\times x-13\right)=18\)
\(42:3\times x-13=18:18\)
\(42:3\times x-13=1\)
\(42:3\times x=1+13\)
\(42:3\times x=14\)
\(14\times x=14\)
\(x=14:14\)
\(x=1\)
Ta có: \(200-18:\left(42:3x-13\right)-28=154\)
\(\Leftrightarrow172-18:\left(42:3x-13\right)=154\)
\(\Leftrightarrow18:\left(42:3x-13\right)=18\)
\(\Leftrightarrow42:3x-13=1\)
\(\Leftrightarrow42:3x=14\)
\(\Leftrightarrow3x=3\)
hay x=1
2. Tìm x biết : a) 13.(25-4x)=13 b) (2x-4).15=0 c) (x-35)-115=0 d) x-36:18=12 e) (x-36):18=12
a: =>25-4x=1
=>4x=24
hay x=6
b: =>2x-4=0
hay x=2
c: =>x-35=115
hay x=150
d: =>x-2=12
hay x=14
e: =>x-36=216
hay x=252
Câu 9: Tìm x biết 7/9 của x là 42.
A. 45 B. 54 C. 36 D. 63
Tìm x thuộc N biết :
A).541+(218-x)=735
B).3636:(12x-91)=36
C).96-3(x+1)=42
D).(x-36):18=12
tìm x,biết:
a,-320+(15-x)=-(-42)
b,|-12|-(x-30)=-7+(x-13)
Tìm x, biết:
11/13 - (5/42 - x) = - (15/28 -11/13)
mong mọi người giúp :)
\(\frac{11}{13}-\left(\frac{5}{42}-x\right)=-\left(\frac{15}{28}-\frac{11}{13}\right)\)
\(\frac{11}{13}-\frac{5}{42}+x=-\frac{15}{28}+\frac{11}{13}\)
\(\frac{-5}{42}+x=-\frac{15}{28}+\left(\frac{11}{13}-\frac{11}{13}\right)\)
\(\frac{-5}{42}+x=-\frac{15}{28}\)
\(x=-\frac{15}{28}+\frac{5}{42}\)
\(x=-\frac{45}{84}+\frac{10}{84}\)
\(x=-\frac{35}{84}\)
Vậy \(x=-\frac{35}{84}\).
\(\frac{11}{13}-\left(\frac{5}{42}-x\right)=\frac{113}{364}\)
\(\left(\frac{5}{42}-x\right)=\frac{11}{13}-\frac{113}{364}\)
\(\left(\frac{5}{42}-x\right)=\frac{15}{28}\)
\(x=\frac{5}{42}-\frac{15}{28}\)
\(x=-\frac{5}{12}\)
vậy \(x=-\frac{5}{12}\)
Bài làm :
Ta có :
\(\frac{11}{13}-\left(\frac{5}{42}-x\right)=-\left(\frac{15}{28}-\frac{11}{13}\right)\)
\(\Leftrightarrow\frac{11}{13}-\left(\frac{5}{42}-x\right)=\frac{113}{364}\)
\(\Leftrightarrow\frac{5}{42}-x=\frac{11}{13}-\frac{113}{364}\)
\(\Leftrightarrow\frac{5}{42}-x=\frac{15}{28}\)
\(\Leftrightarrow x=\frac{5}{42}-\frac{15}{28}=-\frac{5}{12}\)
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