Bài tập 9 trang 41 sgk Toán 8 tập 2 CTST: Giải các phương trình sau:
a) $\frac{3x-1}{6}=\frac{3+2x}{3}$
b) $\frac{x+5}{3}=1-\frac{x-2}{4}$
c) $\frac{3x-}{5}+\frac{3}{2}=\frac{4-x}{10}$
d) $\frac{x}{3}+\frac{2x+1}{6}=\frac{4(x-2)}{5}$
Bài Làm:
a) $\frac{3x-1}{6}=\frac{3+2x}{3}$
$\frac{3x-1}{6}=\frac{2(3+2x)}{6}$
3x -1 = 6 + 4x
4x - 3x = -1 - 6
x = -7
b) $\frac{x+5}{3}=1-\frac{x-2}{4}$
$\frac{4(x+5)}{12}=\frac{12-3(x-2)}{12}$
4x + 20 = 12 - 3x + 6
x = -2
c) $\frac{3x-}{5}+\frac{3}{2}=\frac{4-x}{10}$
$\frac{2(3x-2)}{10}+\frac{15}{10}=\frac{4-x}{10}$
6x - 4 +15 = 4 - x
7x = -7
x = -1
d) $\frac{x}{3}+\frac{2x+1}{6}=\frac{4(x-2)}{5}$
$\frac{10x}{30}+\frac{5(2x+1)}{30}=\frac{12(x-2)}{30}$
10x + 10x + 5 = 24x - 48
4x = 53
$x=\frac{53}{4}$