Okay, so to find like denominators you need to find a number that both denominators go into. For 15, they both go into 45. 9 goes in 5 times and 15 goes in 3 times. So multiply their numerators by 5 and 3. It would be 25/45 for 5/9 and it would be 12/45 for 4/15. Do the same for 16 and 17, for 16 they both go into 42 and for 17 they both go into 42.
You put the equation in slope-intercept form by solving for y.
.. 7y = -6x -42 . . . . . .subtract 6x
.. y = (-6/7)x -6 . . . . . divide by 7
Compare this to the pattern
.. y = mx +b
The slope is the coefficient of x, m = -6/7.
The intercept is the constant term, b = -6.
so it is the second option