Bài 3.Tìm x
a,24+3(5-x)=27
b, x : 4+12=23
c,(x-60):15=20
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a: Ta có: \(100-7\left(x-5\right)=58\)
\(\Leftrightarrow7\left(x-5\right)=42\)
\(\Leftrightarrow x-5=6\)
hay x=11
b: Ta có: \(12\left(x-1\right):3=4^3+2^3\)
\(\Leftrightarrow12\left(x-1\right)=216\)
\(\Leftrightarrow x-1=18\)
hay x=19
Bài 2:
a: \(\Leftrightarrow x-1\in\left\{1;-1;2;-2;3;-3;6;-6\right\}\)
=>\(x\in\left\{2;0;3;-1;4;-2;7;-5\right\}\)
b: \(\Leftrightarrow x+3\in\left\{1;-1;3;-3;5;-5;15;-15\right\}\)
=>\(x\in\left\{-2;-4;0;-6;2;-8;12;-18\right\}\)
c: \(\Leftrightarrow x+3\in\left\{1;-1;2;-2;3;-3;4;-4;6;-6;12;-12\right\}\)
=>\(x\in\left\{-2;-4;-1;-5;0;-6;1;-7;3;-9;9;-15\right\}\)
d: =>x+1+15 chia hết cho x+1
=>\(x+1\in\left\{1;-1;3;-3;5;-5;15;-15\right\}\)
=>\(x\in\left\{0;-2;2;-4;4;-6;14;-16\right\}\)
X – 60 : 15 = 20,5
=> X – 60 = 307,5
=> X = 367,5
X : 4 + 12 = 23
=> X : 4 = 11
=> X = 44
( x – 60 ) : 15 = 20
=> x – 60 = 300
=> x = 360
3 .(x + 7)- 15= 27
=> 3 .(x + 7) = 42
=> x + 7 = 14
=> x = 7
2. ( x – 5 )- 17 = 24 + 6 x 1,5
=> 2. ( x – 5 ) - 17 = 33
=> 2. ( x – 5 ) = 50
=> x - 5 = 25
=> x = 30
\(a,x-60:15=20,5\)
\(x-4=20,5\)
\(x=20,5+4=24,5\)
\(b,x:4+12=23\)
\(x:4=23-12=11\)
\(x=11.4=44\)
\(c,\)\(\left(x-60\right)\)\(:15=20\)
\(x-60=20.15=300\)
\(x=300+60=360\)
\(d,3\left(x+7\right)\)\(-15=27\)
\(3\left(x+7\right)\)\(=27+15=42\)
\(x+7=42:3=14\)
\(x=14-7=7\)
\(e,2\left(x-5\right)\)\(-17=24+6.1,5=24+9=33\)
\(2\left(x-5\right)\)\(=33+17=50\)
\(x-5=50:2=25\)
\(x=25+5=30\)
=>........................
a: =>x/27+1=-2/3
=>x/27=-5/3
=>x=-45
b: \(\Leftrightarrow x-4=\dfrac{2}{5}:\dfrac{20}{21}=\dfrac{2}{5}\cdot\dfrac{21}{20}=\dfrac{42}{100}=\dfrac{21}{50}\)
=>x=221/50
c: \(\Leftrightarrow x+\dfrac{2}{3}=\dfrac{4}{60}=\dfrac{1}{15}\)
=>x=1/15-2/3=1/15-10/15=-9/15=-3/5
d: \(\Leftrightarrow x\cdot\dfrac{3}{5}=\dfrac{1}{5}-\dfrac{15}{14}\cdot\dfrac{21}{20}\)
=>\(x\cdot\dfrac{3}{5}=\dfrac{1}{5}-\dfrac{3}{2}\cdot\dfrac{3}{4}=\dfrac{1}{5}-\dfrac{9}{8}=\dfrac{-37}{40}\)
=>x=-37/24
e: =>-3/7x=84/45
=>x=-196/45
f: =>11/10x=-2/3
=>x=-20/33
Dễ mak
nhưng mik nhìn đề thấy dài quá nên ko muốn làm
hihi^_$
a,x=4 b;x=44 c;x=360
hok tốt
a) \(24+3\left(5-x\right)=27\)
\(\Rightarrow3\left(5-x\right)=27-24\)
\(\Rightarrow3\left(5-x\right)=3\)
\(\Rightarrow5-x=3:3\)
\(\Rightarrow5-x=1\)
\(\Rightarrow x=5-1\)
\(\Rightarrow x=4\)
b) \(x:4+12=23\)
\(\Rightarrow x:4=23-12\)
\(\Rightarrow x:4=11\)
\(\Rightarrow x=11.4\)
\(\Rightarrow x=44\)
c) \(\left(x-60\right):15=20\)
\(\Rightarrow x-60=20.15\)
\(\Rightarrow x-60=300\)
\(\Rightarrow x=300+60\)
\(\Rightarrow x=360\)