數學問題--方程式(快）{40分}

1. 2(3y-7)-5(y-2)=6(y-4)
=> 6y - 14 - 5y + 10 = 6y - 24 ............... 兩邊各自乘開 -- 拆括號
=> y - 4 = 6y - 24
=> y - 4 - y + 24 = 6y - 24 - y + 24 ......... 兩邊各 (- y + 24)
=> 20 = 5y
=> 5y = 20 ............ 左右互調
=> y = 4

2. x/3+2(x-4)=x/2+3
=> [x/3+2(x-4)] * 6 = (x/2+3) * 6 .............. 兩邊各 * 6 使成為整數
=> 2x + 12x - 48 = 3x + 18
=> 14x - 48 = 3x + 18
=> 14x - 48 - 3x + 48 = 3x + 18 - 3x + 48 ......... 兩邊各 (- 3x + 48)
=> 11x = 66
=> x = 6

3. (3-2y/4) + 5/12 = (y-3/2) - 1/3
=> [(3-2y/4) + 5/12] * 12 = [(y-3/2) - 1/3] * 12 .............. 兩邊各 * 12 使成為整數, 12 為所有分母(4, 12, 2, 3) 的最小公倍數
=> 36 - 6y + 5 = 12y - 18 - 4
=> 41 - 6y = 12y - 22
=> 18y = 63
=> y = 7/2

2(3y-7)-5(y-2)=6(y-4)
6Y-14-5Y+10=6Y-24
48=5Y
Y=9.6


x/3+2(x-4)=x/2+3
x/3+2X-8=X/2+3
X/3-X/2+2X=3+8
12=(3X-2X)/-6+2X
-6(12+2X)=X
-72-12X=X
13X=-72
X=-5.538



（3-2y/4）+5/12=（y-3/2）-1/3

2(3y-7)-5(y-2)=6(y-4)
6y-14-5y+10=6y-24
5y=20
y=4

x/3+2(x-4)=x/2+3
6．[x/3+2(x-4)]=6．(x/2+3)
2x+12(x-4)=3X+18
2x+12x-48=3x+18
11x=66
x=6

（3-2y/4）+5/12=（y-3/2）-1/3
12(3-2y/4) +5=12(y-3/2)-4
36-6y+5=12y-18-4
18y=63
y=7/2

1) 2(3y-7)-5(y-2) = 6(y-4)
6y-14-5y+10 = 6y-24
y-4 = 6y-24
5y = 20
y =4
2) x/3 +2(x-4) = x/2 +3
{x/3 +2(x-4)}*6= (x/2 +3)*6
2x+12x-48 = 3x +18
11x = 66
x =6
3) 通分母=12，之後分母可以省略
9-6y+5 = 6y-18-4
12y =36
y= 3

1)
2(3y-7)-5(y-2)=6(y-4)
6y-14-5y+10=6y-24
y-4=6y-24
-5y=-20
y=4

2)
x/3+2(x-4)=x/2+3
全式乘6
2x+12(x-4)=3x+18
2x+12x-48=3x+18
14x-48=3x+18
11x=66
x=6

3)
（3-2y/4）+5/12=（y-3/2）-1/3
全式乘12
3(3-2y)+5=6(y-3)-4
9-6y+5=6y-18-4
-12y=-36
y=3