Giải hộ mik , nhanh lên nhé Bài 3 a) $\frac{3}{5}$ : $\frac{2x}{15}$ = $\frac{1}{2}$ :$\frac{4}{5}$ b) $\frac{-4}{2,5}$ : $\frac{3}{5}$ = $\frac{1

a, $\frac{3}{5}$ : $\frac{2x}{15}$ = $\frac{1}{2}$ : $\frac{4}{5}$

⇔ $\frac{3}{5}$ : $\frac{2x}{15}$ = $\frac{5}{8}$

⇔ $\frac{2x}{15}$ = $\frac{24}{25}$

⇔ 2x = $\frac{72}{5}$

⇔ x = $\frac{36}{5}$

b, $\frac{-4}{2,5}$ : $\frac{3}{5}$ = $\frac{1}{5}$ : x 

⇔ $\frac{1}{5}$ : x = -$\frac{8}{3}$

⇔ x = -$\frac{3}{40}$

c, 0,12 : 3 = 2x : $\frac{3}{5}$

⇔ 2x : $\frac{3}{5}$ = $\frac{1}{25}$

⇔ 2x = $\frac{3}{125}$

⇔ x = $\frac{3}{250}$