Question

Giải phương trình sau:

Answer 1

\(\dfrac{x-10}{70}+\dfrac{x-15}{65}+\dfrac{x-20}{60}=4\)

\(\Leftrightarrow\dfrac{78\left(x-10\right)}{5460}+\dfrac{84\left(x-15\right)}{5460}+\dfrac{91\left(x-20\right)}{5460}=\dfrac{21840}{5460}\)

\(\Leftrightarrow78\left(x-10\right)+84\left(x-15\right)+91\left(x-20\right)=21840\)

\(\Leftrightarrow78x-780+84x-1260+91x-1820=21840\)

\(\Leftrightarrow253x-3860=21840\)

\(\Leftrightarrow253x=25700\)

\(\Leftrightarrow x=\dfrac{25700}{253}\)

Vậy: Phương trình có tập nghiệm \(S=\left\{\dfrac{25700}{253}\right\}\)