In the pair of equations bx - 6y = 18 and 2x - 3y = 9, b is a whole number. The system of two equations has infinitely many solutions. What is the value of b?

I noticed that 6y is2 times 3y and 18 is 2 times 9 so I think that bx will be two times 2x so 4x so 4. (They have to be the same equation to have an infinite amount of solutions so yeah)

I noticed that 6y is2 times 3y and 18 is 2 times 9 so I think that bx will be two times 2x so 4x so 4. (They have to be the same equation to have an infinite amount of solutions so yeah)