Simultaneous equations unique, infinite solutions

hello all, frantic rush to get all the h/w done before school starts again lol.

here it is i have absolutely no idea what i am suppose to do here, the book provides little to no help at all.

This is the example they give which i need help figuring out as well as the actual problem.

Consider the simultaneous linear equations

(m-2)x + y = 2 and mx+2y = k

Find the values of m and k such that the system of equations has

a) a unique solution

b) no solution

c) infinitely many solutions

Now for the question......

Find the value of m for which the simultaneous equations

(m+3)x +my = 12

(m-1)x + (m-3)y = 7

have no solution.

i no that when they want the equations to have no solutions it means the lines are parallel and when the infinite solutions they are the same line however i have no idea what to do about it.

Thanks

Josh