gõ đề bằng công thức toán nếu muốn đc trợ giúp tốt nhất
a, \(\dfrac{x-2}{5}=\dfrac{5}{7}\)
\(\Rightarrow7\left(x-2\right)=25\Rightarrow7x-14=25\)
\(\Rightarrow7x=39\Rightarrow x=\dfrac{39}{7}\)
b, \(\dfrac{-x-2}{3}=\dfrac{-6}{7}\)
\(\Rightarrow7\left(-x-2\right)=-18\Rightarrow-7x-14=-18\)
\(\Rightarrow-7x=-4\Rightarrow x=\dfrac{4}{7}\)
c, \(\dfrac{4}{7-x}=\dfrac{1}{3}\)
\(\Rightarrow12=7-x\Rightarrow7-x=12\)
\(\Rightarrow x=7-12=-5\)
Chúc bạn học tốt!!!
a, \(\dfrac{x-2}{5}=\dfrac{5}{7}\)
\(\Rightarrow7\left(x-2\right)=5^2\)
\(\Rightarrow7x-14=25\)
\(\Rightarrow7x=39\)
\(\Rightarrow x=\dfrac{39}{7}\)
b, \(\dfrac{-x-2}{3}=\dfrac{-6}{7}\)
\(\Rightarrow7\left(-x-2\right)=-6.3\)
\(\Rightarrow-7x-2=-18\)
\(\Rightarrow-7x=-16\)
\(\Rightarrow x=\dfrac{16}{7}\)
c, \(\dfrac{4}{7-x}=\dfrac{1}{3}\)
\(\Rightarrow7-x=4.3=12\)
\(\Rightarrow x=-5\)
