How to split long fraction?

Question

I have a fraction with long numerator, $$ \frac{x1+\ldots+x50}{y}. $$ What is preferred in typing? Or something different?

(1) $$\frac{x1+x2+}{}\qquad\qquad\qquad\qquad\qquad\qquad\qquad(\text{first line})\\ \qquad\qquad\qquad\frac{+x3+x4+\ldots+x50}{y}\qquad(\text{second line}) $$ (2) $$\frac{x1+x2+}{\ldots}\qquad\qquad\qquad\qquad\qquad\qquad\qquad(\text{first line})\\ \qquad\qquad\qquad\frac{+x3+x4+\ldots+x50}{y}\qquad(\text{second line}) $$

Answer 1

Maybe something like

$$ \begin{align} \frac{1}{y} &\Bigl( x_1 + x_2 + x_3 \\ &\qquad + x_4 + x_5 + x_6 \Bigr) \end{align} $$

?