Answer:
x=21/5, also known as 4.2
Step-by-step explanation:
5x:9 = 7:3
Solve it like a proportion and get any of these answers
5x/9 = 7/3
cross product property
3(5x) = 63
15x = 63
x = 63/15 = 21/5 in fraction form = 4.2 in decimal form