Bài 456 Tìm x, biết: 1. 3và2/3vàx + 5và1/2 = 11và1/6
2. 2và3/5vàx – 1/7 = 1 9/35
3. ( 3 4/5 x + 40) : 38/5 = -50
4. (5 1/2 – 2x) . 3/22 = -1 1/2
1) 3$\frac{2}{3}$x+ 5$\frac{1}{2}$ = 11$\frac{1}{6}$
⇔ 3$\frac{3}{2}$x = $\frac{17}{3}$
⇔ x = $\frac{17}{11}$
2) 2$\frac{3}{5}$x – $\frac{1}{7}$ = $\frac{19}{35}$
⇔ 2$\frac{3}{5}$x = $\frac{24}{35}$
⇔ x = $\frac{24}{91}$
3) (3$\frac{4}{5}$x + 40) : $\frac{38}{5}$ = -50
⇔ (3$\frac{4}{5}$x + 40 = -380
⇔ 3$\frac{4}{5}$x = -420
⇔ x = -$\frac{2100}{19}$
4) (5$\frac{1}{2}$ – 2x) . $\frac{3}{22}$ = -1$\frac{1}{2}$
⇔ 5$\frac{1}{2}$ – 2x = -11
⇔ 2x = $\frac{33}{2}$
⇔ x = $\frac{33}{4}$