Look at the first line: y = (3/5)x - 3. What happens if you multiply each term by 5, to eliminate the fraction?
5y = 3x - 3
Compare this to the second equation,
5y - 3x = -10, or 5y = 3x - 10.
The coefficients of x and y (as 3 and 5 here) determine the slope of a straight line. Since 5y = 3x is present in both equations, the two lines MUST be parallel.
y = 4
4y = 6 => y = 6/4
y+4 and y =3/2 are both horizontal lines. Since they are horiz., they are parallel.
