小六數學 - 方程!!!

1) 2/7x - 9 = 21

2/7x-9+9=21+9 2/7x=30 x=30x7/2 x=105

2) 10x+3/8 = 1/5/8

10x+3/8-3/8=13/8-3/8 10x=5/4 x=1/8

3) 3/7Y+0.2 = 1/2

3/7y+0.2-0.2=0.5-0.2 3/7y=0.3 y=0.3x7/3=0.7

1) 2/7x - 9 = 21
2/7 x = 21 + 9
2/7 x = 30
x = 30 x 7/2
x =105

2) 10x+3/8 = 1/5/8
10x = 13/8-3/8
10x = 10/8
x = 10/8 x 1/10
x =1/8

3) 3/7Y+0.2 = 1/2
3/7y = 1/2 - 0.2
3/7y = 1/2 - 2/10
3/7y = 5/10 - 2/10
y = 3/10 x 7/3
y = 7/10

1) 2/7 X - 9 = 21
2/7 X = 30
X = 105

2) 10X + 3/8 = 1/5/8 (我估係1又5/8)
10X = 13/8 -3/8
10X = 10/8
X = 1/8

3) 3/7 Y + 0.2 = 1/2
3/7 Y = 1/2 - 1/5
3/7 Y = (5-2)/10
Y = 3/10 X 7/3
= 7/10