Question

\(\frac{4x}{5}+\frac{5\left(255-x\right)}{4}=255\)

Answer 1

\(\frac{4x}{5}+\frac{5\left(255-x\right)}{4}=255\)

\(\Leftrightarrow\frac{4x.4+25\left(255-x\right)}{20}=255\)

\(\Leftrightarrow16x+25\left(255-x\right)=12,75\)

\(\Leftrightarrow16x+6375-25x=12,75\)

\(\Rightarrow9x=6362,25\)

\(\Rightarrow x=\frac{8483}{12}\)

Answer 2

\(\frac{4x}{5}+\frac{5\left(255-x\right)}{4}=255\)

\(\frac{16x}{20}+\frac{25\left(255-x\right)}{20}=\frac{5100}{20}\)

\(16x+25\left(255-x\right)=5100\)

\(16x+6375-25x=5100\)

\(-9x=-1275\)

\(x=\frac{425}{3}\)

Answer 3

\(\frac{4x}{5}\)+\(\frac{5\left(255-x\right)}{4}\)=255

⇔\(\frac{16x}{20}\)+\(\frac{25\left(255-x\right)}{20}\)=\(\frac{5100}{20}\)

⇒16x+6375-25x=5100

⇔-9x=-1275

⇔ x=\(\frac{-1275}{-9}\)

⇔ x=\(\frac{425}{3}\)

Vậy tập nghiệm của phương trình đã cho là:S={\(\frac{425}{3}\)}