Question 1127111
For parallel, slope will be the same as for 5x+6y=11.  In this form, the left side member will be the same.


For the expected point to be contained,  
{{{5x+6y=5(-6)+6(-9)}}}

{{{5x+6y=-30-54}}}

{{{highlight(5x+6y=-84)}}}

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If you want y as the function, f(x), the solve for y and simplify...