伐數分式及公式9(請盡快回答)

3a
x+y+z=360
z=360-x-y

3b
2y=5x
x=2y/5

4a
y=3x-2
x=(y-2)/3

4b
3y=6x+8
x=(3y-8)/6

5a
a=(b-7)/4
b=4a+7

5b
p=(6-3q)/4
4p-6=-3q
q=(6-4p)/3

8a
y/(x+2)=8
y/8=x+2
x=y/8 +2

8b
x=y/(x+2)
1+3z=y/x
y/x -1=3x
(y-x)/x=3z
z=(y-x)/(3x)

10b
p/3 +11=4(a/2 +1)
(p+33)/3=2q+2
p+33=6q+6
p+27=6q
q=(p+27)/6

11b
1/(2a)+1/(4b)-1/(3a)=1/b
(1/a)(1/2-1/3)=(1/b)(1-1/4)
(1/a)(1/6)=(1/b)(3/4)
4b=18a
a=2b/9