Question

giải phương trình sau

1) \(\dfrac{x}{45}+\dfrac{x}{40}=\dfrac{1}{6}\)

Answer 1

\(\dfrac{x}{45}\) + \(\dfrac{x}{40}\) = \(\dfrac{1}{6}\)

⇔ \(\dfrac{40x}{1800}\) + \(\dfrac{45x}{1800}\) = \(\dfrac{300}{1800}\)

⇔ 40x + 45x = 300

⇔ 85x = 300

⇔ x = \(\dfrac{60}{17}\)

Vậy x = \(\dfrac{60}{17}\)

Answer 2

\(\dfrac{x}{45}+\dfrac{x}{40}=\dfrac{1}{6}\)

\(\Leftrightarrow\dfrac{x}{9}+\dfrac{x}{8}=\dfrac{5}{6}\)

\(\Leftrightarrow\dfrac{17x}{72}=\dfrac{5}{6}\)

\(\Leftrightarrow102x=360\)

\(\Leftrightarrow x=\dfrac{60}{17}\)

Vậy \(S=\left\{\dfrac{60}{17}\right\}\)

đúng ko nhỉ???

Answer 3

\(\dfrac{x}{45}+\dfrac{x}{40}=\dfrac{1}{6}\)

\(\Leftrightarrow\dfrac{8x}{360}+\dfrac{9x}{360}=\dfrac{60}{360}\)

\(\Leftrightarrow8x+9x=60\)

\(\Leftrightarrow17x=60\)

\(\Leftrightarrow x=\dfrac{60}{7}\)

Vậy phương trình có nghiệm \(x=\dfrac{60}{7}\)