8:7 plus 2x equals 13:5 (simple equation) simple and slightly complex equation! Quick, I just need an answer

8:7 plus 2x equals 13:5 (simple equation) simple and slightly complex equation! Quick, I just need an answer

Subtract 8.7 from both sides
8.7+2x-8.7=13.5-8.7
2x=4.8
x=4.8÷2
x=2.4