12(2-3x)=4x+4
24-36x=4x+4
24-4=36x+4x
20=40x
x=20/40=1/2
6-3(x+ 2/3 )=2/3
6-3x-3*3/3=2/3
6-3x-2=2/3
6-2-2/3=3x
10/3=3x
x=10/9
2(200-15x)=70+25x
400-30x=70+25x
400-70=30x+25x
330=55x
x=330/55=6
3(2x+1)=12
6x+3=12
6x=12-3
6x=9
x=9/6=3/2
c=5/9(f-32).一直c=15℃,求f.
15=5/9(f-32)
15*9/5=f-32
27=f-32
f=27+32=59