Exercise 4 Page 198

Equivalent expressions are equal no matter what number is substituted for the same variable in the expressions. Consider the given expression. - 3 + 2/3y - 4 - 1/3y We can see that there are two y-terms and two constants in the expression. We can get an equivalent expression by combining like terms. To do so, we will use the Commutative Property of Addition and the Associative Property of Addition.

- 3 + 2/3y - 4 - 1/3y

CommutativePropAdd

Commutative Property of Addition

2/3y - 1/3y + (- 3) - 4

AssociativePropAdd

Associative Property of Addition

(2/3y - 1/3y) + (- 3 - 4)

SubTerms

Subtract terms

1/3y + (- 7)

AddNeg

a+(- b)=a-b

1/3y - 7

Note that each step of our solution is an equivalent expression. Keep in mind that there are other possible answers besides the ones given here.