Tìm x, biết:
a, x/5=2/5
x=2
b, 3/8=6/x
3x=6.8
3x=48
x=16
c, 1/9=x/27
27=9x
x=3
d, 4/x=8/6
4.6=8x
8x=24
x=3
e, 3/x-5=4/x+2
3(x+2)=4(x-5)
3x+6=4x-20
3x-4x=-20-6
-x=-26
x=26
f, x/-2=8/x
x.x=-2.8
x2=-16(vô lí)
a) \(\frac{x}{5}=\frac{2}{5}\Rightarrow5x=10\Rightarrow x=2\)
b) \(\frac{3}{8}=\frac{6}{x}\Rightarrow3x=48\Rightarrow x=16\)
c) \(\frac{1}{9}=\frac{x}{27}\Rightarrow9x=27\Rightarrow x=3\)
d) \(\frac{4}{x}=\frac{8}{6}\Rightarrow24=8x\Rightarrow x=3\)
e) \(\frac{3}{x-5}=\frac{4}{x+2}\Rightarrow3\left(x+2\right)=4\left(x-5\right)\)
\(\Rightarrow3x+6=4x-20\)
\(\Rightarrow20+6=x\)
\(\Rightarrow x=26\)
Bài làm
a) \(\frac{x}{5}=\frac{2}{5}\)
Vì \(\frac{x}{5}=\frac{2}{5}\)mà hai phân số này có cùng mẫu số
=> x = 2
Vậy x = 2
b) \(\frac{3}{8}=\frac{6}{x}\)
\(\Rightarrow3.x=6.8\)
\(\Rightarrow3.x=24\)
\(\Rightarrow x=24:3\)
\(\Rightarrow x=8\)
Vậy x = 8
Bài làm
c) \(\frac{1}{9}=\frac{x}{27}\)
\(\Rightarrow x.9=1.27\)
\(\Rightarrow x.9=27\)
\(\Rightarrow x=27:9\)
\(\Rightarrow x=3\)
Vậy \(x=3\)
d) \(\frac{4}{x}=\frac{8}{6}\)
\(\Rightarrow x.8=6.4\)
\(\Rightarrow x.8=24\)
\(\Rightarrow x=24:8\)
\(\Rightarrow x=3\)
Vậy \(x=3\)
# Chúc bạn học tốt #
a, \(\frac{x}{5}\)=\(\frac{2}{5}\)=> x=2
vậy x=2
b,\(\frac{3}{8}\)=\(\frac{6}{x}\)=>3.x=6.8
=>3.x=48
=>x=16
vậy x=16
c,\(\frac{1}{9}\)=\(\frac{x}{27}\)=>9.x=27
=>x=3
vậy x=3
d,\(\frac{4}{x}\)=\(\frac{8}{6}\)=>8.x=24
=>x=3
vậy x=3
e,\(\frac{3}{x-5}\)=\(\frac{4}{x+2}\)=> 3(x+2)=4(x-5)
=> 3x+6=4x-20
=>3x-4x=-20-6
=>x=26
vậy x=26
f, \(\frac{x}{-2}\)=\(\frac{8}{x}\)=>\(x^2\)=-16 -> vô lí
