Question

Tìm x: \(\dfrac{3x-5}{7}=\dfrac{2x+1}{13}\)

Answer 1

\(\dfrac{3x-5}{7}=\dfrac{2x+1}{13}\)

Ta có: \(\left(3x-5\right).13=\left(2x+1\right).7\)

\(=>39x-65=14x+7\)

\(=>39x-14x=7+65\)

\(=>25x=72\)

\(=>x=72:25\)

Vậy \(x=\dfrac{72}{25}\)

_{(* Công thức: Hai phân số bằng nhau thì hai nhân chéo cũng bằng nhau )}

Answer 2

(3x - 5)/7 = (2x + 1)/13

13.(3x - 5) = 7.(2x + 1)

39x - 65 = 14x + 7

39x - 14x = 7 + 65

25x = 72

x = 72/25