數學題:主項變換

1.)

x = (a+b+c+2d-15)/5
a = 5x-b-c-2d+15
b = 5x-a-c-2d+15
c = 5x-a-b-2d+15
d = (5x-a-b-c+15)/2



x = (a+b+c+2d/3) /5
a = 5x-b-c-2d/3
b = 5x-a-c-2d/3
c = 5x-a-b-2d/3
d = (15x-3a-3b-3c)/2

1. x= (a b c 2d-15)/5


2. x =( a b c 2d)/15



大約係咁..希望無計錯喇*