tolong cari nilai x caranya

7/(7+5)=9/(9+x)
7/12=9/(9+x)
63+7x=108
7x =45
x=45/7 =6,4..[B]

(x+9)/9 = (5+7) /7
x+9/9 = 12/7
7(x+9) = 108
7x+63 = 108
7x = 108-63
7x = 45
x = 45/7 = 6,4

semoga bisa membantu!! terima kasih