登录
1. 方程$5x - 2 = 8$的解为______.
答案
x=2
解析
解：$5x - 2 = 8$
$5x = 8 + 2$
$5x = 10$
$x = 2$
$5x = 8 + 2$
$5x = 10$
$x = 2$
2. 方程$-2x + 6.2 = -2.8$的解为______.
答案
x=$\frac{9}{2}$
解析
解：$-2x + 6.2 = -2.8$
$-2x = -2.8 - 6.2$
$-2x = -9$
$x = \frac{9}{2}$
$-2x = -2.8 - 6.2$
$-2x = -9$
$x = \frac{9}{2}$
3. 方程$3x - 7 = -11x$的解为______.
答案
x=$\frac{1}{2}$
解析
解：$3x + 11x = 7$
$14x = 7$
$x = \frac{7}{14}$
$x = \frac{1}{2}$
$14x = 7$
$x = \frac{7}{14}$
$x = \frac{1}{2}$
4. 方程$-12 = 4x + 2x$的解为______.
答案
x=-2
解析
解：$-12 = 4x + 2x$
$6x = -12$
$x = -2$
$6x = -12$
$x = -2$
5. 方程$-\frac{4y}{9} + 7 = -2y$的解为______.
答案
y=-$\frac{9}{2}$
解析
解：$-\frac{4y}{9} + 7 = -2y$
移项得：$-\frac{4y}{9} + 2y = -7$
通分得：$-\frac{4y}{9} + \frac{18y}{9} = -7$
合并同类项得：$\frac{14y}{9} = -7$
系数化为1得：$y = -7 × \frac{9}{14} = -\frac{9}{2}$
$y=-\frac{9}{2}$
移项得：$-\frac{4y}{9} + 2y = -7$
通分得：$-\frac{4y}{9} + \frac{18y}{9} = -7$
合并同类项得：$\frac{14y}{9} = -7$
系数化为1得：$y = -7 × \frac{9}{14} = -\frac{9}{2}$
$y=-\frac{9}{2}$
6. $\frac{11}{9}x + \frac{2}{7} = \frac{2}{9}x - \frac{5}{7}$
答案
x=-1
解析
解：$\frac{11}{9}x - \frac{2}{9}x = -\frac{5}{7} - \frac{2}{7}$
$x = -1$
$x = -1$
7. $\frac{3}{4}y - 5 = -y + 11 - \frac{1}{4}y$
答案
y=8
解析
解：$\frac{3}{4}y - 5 = -y + 11 - \frac{1}{4}y$
$\frac{3}{4}y + y + \frac{1}{4}y = 11 + 5$
$2y = 16$
$y = 8$
$\frac{3}{4}y + y + \frac{1}{4}y = 11 + 5$
$2y = 16$
$y = 8$
8. $6y - \frac{3}{4} = 4y + \frac{5}{4}$
答案
y=1
解析
解：$6y - 4y = \frac{5}{4} + \frac{3}{4}$
$2y = 2$
$y = 1$
$2y = 2$
$y = 1$
9. $10x + 7 = 16x - 5 - 3x$
答案
x=4
解析
解：$10x + 7 = 16x - 5 - 3x$
$10x + 7 = 13x - 5$
$10x - 13x = -5 - 7$
$-3x = -12$
$x = 4$
$10x + 7 = 13x - 5$
$10x - 13x = -5 - 7$
$-3x = -12$
$x = 4$
10. $3 + \frac{x}{2} = 3x - 1$
答案
x=$\frac{8}{5}$
解析
解：$3 + \frac{x}{2} = 3x - 1$
$\frac{x}{2} - 3x = -1 - 3$
$-\frac{5x}{2} = -4$
$x = \frac{8}{5}$
$\frac{x}{2} - 3x = -1 - 3$
$-\frac{5x}{2} = -4$
$x = \frac{8}{5}$
11. $x - 1 - \frac{1}{2}x = 3 - 0.5x - 2$
答案
x=2
解析
解：$x - 1 - \frac{1}{2}x = 3 - 0.5x - 2$
$\frac{1}{2}x - 1 = 1 - 0.5x$
$\frac{1}{2}x + 0.5x = 1 + 1$
$x = 2$
$\frac{1}{2}x - 1 = 1 - 0.5x$
$\frac{1}{2}x + 0.5x = 1 + 1$
$x = 2$
12. $\frac{7}{13}x - 4 = \frac{12}{13}x + 1$
答案
x=-13
解析
解：$\frac{7}{13}x - \frac{12}{13}x = 1 + 4$
$-\frac{5}{13}x = 5$
$x = 5 × (-\frac{13}{5})$
$x = -13$
$-\frac{5}{13}x = 5$
$x = 5 × (-\frac{13}{5})$
$x = -13$
13. $-\frac{2}{3}x - 10 = 2 - \frac{3}{4}x$
答案
x=144
解析
解：$-\frac{2}{3}x - 10 = 2 - \frac{3}{4}x$
移项，得$-\frac{2}{3}x + \frac{3}{4}x = 2 + 10$
通分，得$-\frac{8}{12}x + \frac{9}{12}x = 12$
合并同类项，得$\frac{1}{12}x = 12$
系数化为1，得$x = 144$
移项，得$-\frac{2}{3}x + \frac{3}{4}x = 2 + 10$
通分，得$-\frac{8}{12}x + \frac{9}{12}x = 12$
合并同类项，得$\frac{1}{12}x = 12$
系数化为1，得$x = 144$
