If the System Has Infinitely Many Solutions, Write the Solution

Multiple Choice

If the system has infinitely many solutions, write the solution set with x arbitrary.
- $$\begin{array} { l } \frac { 9 } { x } + \frac { 1 } { y } = \frac { 29 } { 28 } \\\frac { - 6 } { x } - \frac { 1 } { y } = - \frac { 17 } { 28 }\end{array}$$

A) $\{ ( - 42 , - 4 ) \}$

B) $\{ ( - 4,7 ) \}$

C) $\{ ( 7 , - 4 ) \}$

D) $\{ ( - 7,4 ) \}$