1. Use the associative property to rewrite the expression 97 + (3 + 13)

Question

I rewrote this as (97 + 3) + 13 since the associative property is about changing the grouping. The answer in the back of the book says 97 + (3 + 13) -- the same as the original problem.

2. Use the distributive property to simplify (2x + 3) - (x - 6)
I got -2x squared + 9x + 18 but the answer in the back of the book says x + 9

Could you explain where I went wrong on this problem please?

Answer 1

Why did you square 2x?

(2x + 3) - (x - 6)

2x - x = x
3 + 6 = 9

(2x + 3) - (x - 6) = x + 9

Answer 2

I think I was looking at it as the two parentheses were multiplied together but I see now! Thank you.

What about the first question?

Answer 3

You are right about the first question.

You're welcome.

Answer 4

97 + 16 = 113