[Hiddos]

I think it's rather obvious:

Код:

3x^2 = 6x
x^2 - 2x = 0
x(x - 2) = 0

Now I think you've learned that this concludes that x = 0 v x = 2. For some proof, let's fill in those x's:

Код:

x(x - 2)

x = 0:

0 * (0 - 2)

If you multiply something with zero, it's zero.

Код:

x = 2

2 * (2 - 2) -> 2 * 0

Multiply with zero, stays zero.

If you fill in x = 3:

Код:

3 * (3 - 2) -> 3 * 1 = 3

Got it?