6下B--14簡易方程(二)
1. 2(d - 6) = 8
2d - 12 = 8
2d + 12 -12 = 8 + 12
2d = 20
d = 10
2. 2 + C/3 = 5
2 + C/3 - 2 = 5 - 2
C/3 = 3
C = 9
3. 4a + 5 = 61
4a +5 -5 = 61 - 5
4a = 56
4a/4 = 56/4
a = 14
4. 0.75 + 3y = 1.17
0.75 + 3y - 0.75 = 1.17 - 0.75
3y = 0.42
3y/3 = 0.42/3
y = 0.14
5. 3(X - 4) = 9
3X - 12 = 9
3X - 12 + 12 = 9 + 12
3X /3 = 21 /3
X = 7
驗算：
當 X = 7 ,
左邊 = 3 (7 - 4)
= 3 (3)
= 9
= 右邊
6. (B + 7.5) / 5 = 2
B + 7.5 = 10
B = 10 - 7.5
B = 2.5
驗算：
當 B = 2.5 ,
左邊 = (2.5 + 7.5)/5
= 10/5
= 2
= 右邊
7. (3/4)/m - 1.9 = 1.7
(3/4)m - 1.9 + 1.9 = 1.7 + 1.9
(3/4)m x 4/3 = 3.6 x 4/3
m = 4.8
驗算：
當 m = 4.8 ,
左邊 = (3/4) x 4.8 - 1.9
= 3.6 - 1.9
= 1.7
= 右邊
8. P/6 + 2/3 = 1(1/4)
P/6 + 2/3 - 2/3 = 1(1/4) - 2/3
P/6 = 15/12 - 8/12
P/6 x 6 = 7/12 x 6
P = 7/2
驗算：
當 P = 7/2 ,
左邊 = (7/2)/6 + 2/3
= 7/12 + 8/12
= 15/12
= 1(1/4)
= 右邊
9. 1.6x - 0.39 + 0.39 = 0.09 + 0.39
1.6x = 0.48
1.6w/1.6 = 0.48/1.6
w = 0.3
驗算：
當 w = 0.3 ,
左邊 = 1.6x - 0.39
= 1.6(0.3) - 0.39
= 0.09
= 右邊
10. 3(L-4)/4 x 5/4 = 4 x 5/3
L - 4 = 20/3
L - 4 + 4 = 6(2/3) + 4
L = 10(2/3)
驗算：
當 L = 10(2/3) ,
左邊 = 3(L - 4)/5
= 3( 10(2/3) )/5
= 4
= 右邊
11. (H + 7) x 45/100 = 9
(H + 7) x 45/100 x 100/45 = 9 x 100/45
H + 7 = 20
H + 7 - 7 = 20 - 7
H = 13
驗算：
當 H = 13 ,
左邊 = (H + 7) x 45%
= ( 13 + 7) x 45/100
= 9
= 右邊
12. 5t/6 - 5/2 = 3/4
5t/6 - 5/2 + 5/2 = 3/4 + 5/2
5t /6 = 13/4
5t/6 x 6/5 = 13/4 x 6/5
t = 39/10
t = 3(9/10)
驗算：
當 t = 3(9/10 ,
左邊 = 5t/6 - 2(1/2)
= 5 x 3(9/10 / 6 - 2(1/2)
= 3/4
= 右邊
