Exercise 30 Page 239

To evaluate the given expression for a=-6, first, we should substitute -6 for a in the given expression. When multiplying real numbers, the product will be positive if the signs are the same and it will be negative if the signs are different. cc Same Sign & Different Signs (+)(+)=(+) & (+)(-)=(-) (-)(-)=(+) & (-)(+)=(-) We will use the Associative Property of Multiplication to multiply the first two numbers first. There are two negative numbers so the product will be positive.

-3(- 6)

MultNegNegOnePar

- a(- b)=a* b

3* 6

IdPropMult

Identity Property of Multiplication

18

Now we will multiply the remaining two numbers. The result of the first multiplication was positive and the third number is negaitve, so the final product will be negative.

18(-6)

MultPosNeg

a(- b)=- a * b

-18 * 6

Multiply

Multiply

-108