Answer:
So we can see that these are similar shapes. So we can get a ratio for this'
21:51 is our ratio now we just need to compare to our second ratio
2x+3:34. So now we just need to get our multiplier which will be 34/51 because we're getting smaller. So we just need to multiply it by 21
21*34/51 = 14. So now we know that 14 = 2x+3
14 = 2x+3. Do simple algebra and get x = 11/2.
11/2 or 5 1/2 or 5.5 is answer