Tolong bantu no 1 dan 2 yaa makasih

1a)
[tex] \frac{13}{18} = \frac{6,5}{x} [/tex]
kali silang
2x=18
x=9
 
b)
[tex] \frac{12}{20} = \frac{y}{10} [/tex]
5y = 30
y=6

c)
[tex] \frac{7}{14} = \frac{3}{(3+z)} [/tex]
3+z = 6
z=3

2. 
[tex] \frac{8}{8+2x} = \frac{6}{9}
16+4x =24
4x=8
x=2