Name which property is shown in 7 · 9 · (-3) = (-3) · 7 · 9 a) associative property of multiplication b) commutative property of multiplication c) identity property d) distributive property

Pls , the question is in the picture!

Ageologist had two rocks on a scale that weighed 4.6 kilograms together.rock a was 0.5 of the total weight.how much did rock a weigh?

Offering 30 if a plus b plus c equals 68 and ab plus bc plus ca equals 1121, where a, b, and c are all prime numbers, find the value of abc. the answer is 1978 but i need an explanation on how to get that.