Given that x and y satisfy the simultaneous equations

mx + (m-1)y = 10

(m-2)x + 3my = 20

(a) If the equations have no unique solution, find the values of m. [1/2, -2]

(b) If the equations have no solutions, find the values of m. [1/2]

(c) If m =3, solve the simulataneous equations [x=2, y =2]

Can this question be solved by NOT using the determinant method (i.e. b^2 - 4ac)

For part a), this implies b^2 - 4ac = 0 (right?)

For part b), this implies b^2 - 4ac = ?

Thank you.