-0.3x(-1.2x - 0.3x + 0.50)

The distributive property means you must "distribute" the -0.3x in front of the brackets by multiplying it by each term in the bracket.Thus:

= (-1.2x)(-0.3x) - (0.3x)(-0.3x) + (0.50)(-0.3x)

= `(0.36x^2) - (- 0.09x^2) + (-0.15x)`

Note how some of the symbols have changed when we multiply by a negative (-). Now simplify those negatives and remove brackets:

= `0.36x^2 + 0.09x^2 - 0.15x`

We have "like terms" so can add them together.

= **0.45x^2 - 0.15x**