唔該幫我計計d maths(中一)

28y=3[16-4(1-y)]
28y/3=16-4+4y
(28y/3)-4y=12
y=2.25

7[2(x-3)+x]=4[1-3(x+1)]
7[3x-6]=4[-2-3x]
21x-42=-8-12x
33x=34
x=34/33

[5(3-x)]/8-(x+3)/2=0
[15-5x]=4x+12
9x=3
x=1/3

(t+1)/3-(a+4)/4=a+1
4t+4-3a-12=12a+12
4t=15a+20
t=5(3a+4)/4