b)\(\frac{28}{100}x+\frac{4}{25}+\frac{10}{4}=\frac{203}{50}\)
<=>\(\frac{28}{100}x=\frac{203}{50}-\frac{10}{4}-\frac{4}{25}=\frac{406-250-16}{100}\)
<=>\(\frac{28}{100}x=\frac{140}{100}\)
<=>\(x=\frac{140}{100}:\frac{28}{100}=\frac{140}{100}.\frac{100}{28}\)
<=>x=5
a) \(\frac{1}{2}x+\frac{9}{4}-\frac{8}{20}=\frac{77}{20}\)
=> \(\frac{1}{2}x=\frac{77}{20}+\frac{8}{20}-\frac{9}{4}=2\)
=> \(\frac{x}{2}=2\Rightarrow x=2\cdot2=4\)
vậy x = 4
b) \(\frac{28}{100}x+\frac{4}{25}+\frac{10}{4}=\frac{203}{50}\)
=> \(\frac{28}{100}x=\frac{203}{50}-\frac{10}{4}-\frac{4}{25}=1\frac{2}{5}=\frac{7}{5}\)
=> \(\frac{28x}{100}=\frac{7}{5}\Rightarrow28x=\frac{100\cdot7}{5}=140\Rightarrow x=140:28=5\)
vậy x = 5
c) \(\frac{100}{58}=\frac{1}{2}x\)
=> \(\frac{100}{58}=\frac{x}{2}\Rightarrow x=\frac{100\cdot2}{58}=3\frac{13}{29}=\frac{100}{29}\)
vậy x = 100/29