a. Two properties are involved. 1) the additive inverse property of addition that says -1 +1 = 0, and 2) the substitution property of equality that says -1+1 can be substituted for 0.
b. The distributive property.
c. The identity property of multiplication.
d. Here, there are three properties involved. 1) the addition property of equality tha says I can add -3 to both sides of the equation; 2) the additive inverse property that says -3+3 = 0; and 3) the identity property of addition that says ( )+0 = ( ).
