F.1Math

4(y-10)+1/3y=25
4y-40+1/3y=25
4y+1/3y=25+40
13/3y=65
y=65除 13/3
y=15

4(y-10)+1/3y=25
4y-40+1/3y=25
4y-40+40+1/3y=25+40
4y+1/3y=65
4y+y/3=65
4y+y=195
5y=195
y=39

其實我有d唔明你條式.......(sor)
因為我唔知係3y份之一定3份之y(我唔知個y係唔係擺係份線ge中間定點....)
佢地都唔同計法
而我就計咗3份之y嗰個
so如果我計錯咗請原諒!!

4(y-10)+1/3y=25
=> 4y - 40 + 1/3y = 25 .......... 拆括號
=> 4y - 40 + 1/3y + 40 = 25 + 40 .......... 兩邊各 + 40
=> 4y + 1/3y = 65
=> 3 (4y + 1/3y) = 3 * 65 .......... 兩邊各乘 3 除去 1/3 的分母
=> 12y + y = 195
=> 13y = 195
=> y = 15 .......... 兩邊各除 13

(4yx3)-(40x3)+(1/3y)x3=25x3
12y-120+y=75
13y=75+120
y=195/13
y=15

4(y-10)+1/3y=25
4y -40 +1 = 75y
-39 = 71y
y = -39/71