升中一暑期作業問題(方程式) (((急)))

(a) 5x + 3 = 48
5x = 45
x = 15
(b) 12x - 8 = 16
12x = 24
x = 2
(c) 4x + 6 = 30
4x = 24
x = 6
(d) 6 ( x + 2 ) = 12
x + 2 = 2
x = 0
(e) 1/6 ( 27 - 3x ) = 6
27-3x = 36
-9 = 3x
x = -3
(f) 3/14*( 2x + 7 ) = 1
3(2x+7) = 14
6x + 21 = 14
6x = -7
x = -7/6
(g) 2/7*( 3x + 7 ) + 1 = 9
7[2/7*(3x+7) + 1] = 7(9)
2(3x+7) + 7 = 63
2(3x+7) = 56
3x+7 = 28
3x = 21
x = 7
(h) 5/9 * ( x + 2 ) = 3/18 * ( 3x + 8 )
18[5/9 * (x+2)] = 18[3/18 * (3x+8)]
10(x+2) = 3(3x+8)
10x + 20 = 9x + 24
x = -4

(a) 5x + 3 = 48
5x=48-3
5x=45
x=45/5
x=9

(b) 12x - 8 = 16
12x=16+8
12x=24
x=24/12
x=2

(c) 4x + 6 = 30
4x=30-6
4x=24
x=24/4
x=6

(d) 6 ( x + 2 ) = 12
x+2=12/6
x+2=2
x=2-2
x-0

(e) 6分之1 ( 27 - 3x ) = 6
27 - 3x =6/6分之1
27 - 3x =36
-3x=36-27
-3x=9
x=9+3
x=11

(f) 14分之3 ( 2x + 7 ) = 1
3(2x+7) = 14
6x + 21 = 14
6x = 14-21
6x = -7
x = -7/6

(g) 7分之2 ( 3x + 7 ) + 1 = 9
2(3x+7) + 1 = 7(9)
2(3x+7) + 1 = 63
2(3x+7) = 63-1
2(3x+7) =62
3x+7 =62/2
3x+7 = 31
3x=31-7
3x = 24
x =24/3
x =8

(h) 9分之5 ( x + 2 ) = 18分之3 ( 3x + 8 )
18[9分之5 (x+2)] = 18[18分之3 (3x+8)]
10(x+2) = 3(3x+8)
10x + 20 = 9x + 24
10x-9x = 24-20
x = 4