写真に写っている計算問題（1番と2番）を解く。

1. 問題の内容

写真に写っている計算問題（1番と2番）を解く。

2. 解き方の手順

(1) 3x + 2x

$3x + 2x = (3+2)x = 5x$

(2) -x + 3x + 4x

$-x + 3x + 4x = (-1+3+4)x = 6x$

(3) a - 5 - 4a

$a - 5 - 4a = a - 4a - 5 = (1-4)a - 5 = -3a - 5$

(4) -5a + 2 - 3a - 6

$-5a + 2 - 3a - 6 = -5a - 3a + 2 - 6 = (-5-3)a - 4 = -8a - 4$

(5) (2/3)x - 1 + (1/3)x + 4

$\frac{2}{3}x - 1 + \frac{1}{3}x + 4 = \frac{2}{3}x + \frac{1}{3}x - 1 + 4 = (\frac{2}{3} + \frac{1}{3})x + 3 = \frac{3}{3}x + 3 = x + 3$

(6) (3/2)x - 3 - (2/3)x - (1/4)x

$\frac{3}{2}x - 3 - \frac{2}{3}x - \frac{1}{4}x = \frac{3}{2}x - \frac{2}{3}x - \frac{1}{4}x - 3 = (\frac{3}{2} - \frac{2}{3} - \frac{1}{4})x - 3$

$= (\frac{18}{12} - \frac{8}{12} - \frac{3}{12})x - 3 = \frac{7}{12}x - 3$

(1) x + (3x - 1)

$x + (3x - 1) = x + 3x - 1 = (1+3)x - 1 = 4x - 1$

(2) 2x + 1 - (4x + 3)

$2x + 1 - (4x + 3) = 2x + 1 - 4x - 3 = 2x - 4x + 1 - 3 = (2-4)x - 2 = -2x - 2$

(3) (-x - 3) + (x + 7)

$(-x - 3) + (x + 7) = -x - 3 + x + 7 = -x + x - 3 + 7 = 0x + 4 = 4$

(4) (3a + 4) - (-a + 6)

$(3a + 4) - (-a + 6) = 3a + 4 + a - 6 = 3a + a + 4 - 6 = (3+1)a - 2 = 4a - 2$

(5) (-(1/5)x + 3) - ((4/5)x - 5)

$(-\frac{1}{5}x + 3) - (\frac{4}{5}x - 5) = -\frac{1}{5}x + 3 - \frac{4}{5}x + 5 = -\frac{1}{5}x - \frac{4}{5}x + 3 + 5 = (-\frac{1}{5} - \frac{4}{5})x + 8 = -\frac{5}{5}x + 8 = -x + 8$

(6) ((2/3)x + 1) - ((3/4)x - 2)

$(\frac{2}{3}x + 1) - (\frac{3}{4}x - 2) = \frac{2}{3}x + 1 - \frac{3}{4}x + 2 = \frac{2}{3}x - \frac{3}{4}x + 1 + 2 = (\frac{2}{3} - \frac{3}{4})x + 3$

$= (\frac{8}{12} - \frac{9}{12})x + 3 = -\frac{1}{12}x + 3$

3. 最終的な答え

**1.**

(1) 5x

(2) 6x

(3) -3a - 5

(4) -8a - 4

(5) x + 3

(6) (7/12)x - 3

**2.**

(1) 4x - 1

(2) -2x - 2

(3) 4

(4) 4a - 2

(5) -x + 8

(6) (-1/12)x + 3