Explain how to use properties to prove d + (8d + 1) + 7 is equivalent to 8 + 9d.

Use the associative property to move the parentheses, and the expression becomes (d + 8d) + 1 + 7. Combine like terms, and the expression becomes 9d +8. Use the commutative property to change the order of the terms, and the expression becomes 8 + 9d.

Step-by-step explanation:

a) false; the points do not have to be in a straight line.

step-by-step explanation:

the points could be in the shape of a triangle

b is incorrect

c is incorrect because it is saying the immediately don't form one when they are capable of doing so

d is incorrect

a

step-by-step explanation: