To solve this equation, we first convert 5.1 and 8.7 to fractions.

5.1 = 5 + 1/10 = 51/10
8.7 = 8 + 7/10 = 87/10

Now, we can rewrite the equation as:

51/10 ÷ 87/10 = 34y/29

To divide two fractions, we multiply the first fraction by the reciprocal of the second fraction:

51/10 * 10/87 = 34y/29

Simplify the equation:

51/87 = 34y/29

Reduce the fractions:

17/29 = 34y/29

Now, we can see that y = 17/34 = 0.5

So, the solution to the equation is y = 0.5