Die korrekte Antwort lautet:
-12 ⋅ 0 = 0

$(13-\left(26+14\right))·20$

= $\left(13-26-14\right)·20$

= $-27·20$

= $-540$

$-3\cdot {\left(-2\right)}^3-{\left(-3\right)}^2$

= $-3\cdot \left(-8\right)-9$

= $24-9$

= $15$