Solve the Equation: Finding the Missing Factor in (-3)⬜ = -15

Let's remember the rule:

$(-x)\times(+x)=-x$

Let's think about what number we need to multiply by 3 to get 15:

$3\times5=15$

Now let's put the numbers together with the appropriate sign as written in the rule above, and we get:

$-3\times(+5)=-15$