First you turn the equation into y=mx+b form.
2y-3x=10
2y=3x+10
2y/2=(3x+10)/2
y=3/2x+5
Next you take the opposite of the slope.
Slope = 3/2
Opposite = 2/3
Then you insert your values into y-y1=m(x-x1)
y+1=2/3(x+8)
y+1=2/3x+16/3
The answer is
y=2/3x+13/3