Asystem of equations has no solution. if y = 8x + 7 is one of the equations, which could be the other equation?

y = 8x + 7
y = 8x – 7
y = –8x + 7
y = –8x – 7

For the answer to the question above, a system of equations has no solution when the lines representing the equation are parallel but do not coincide. For two lines to be parallel, the must have the same gradient i.e. coefficient of x when y is made the subject of formula must be equal.
If one of the equations is
y = 8x + 7,
then the other equation will be
y = 8x - 7