Question

Directions: Determine whether each trinomial is a perfect square. If so, factor it.

2. 4a^2+4a+1
Answer: 2(a+1)^2

3. 9m^2+15m+25
Answer: no

4. d^2-22d+121
Answer: (d-11)^2

Directions: Determine whether each binomial is the difference of squares. If so, factor it.

5. x^2-16
Answer: (x-4)(x+4)

6. y^2-20
Answer: no

7. 16m^2-25n^2
Answer: (m+4)-(5+n)

8. 8a^2-18
Answer: (7+ab)-(7-ab)

Answer 1

#2, no
all you had to do is expand your answer to see that it can't be right.
should have been (2a + 1)^2

#7, your answer is not in factored form, it shows a subtraction, not a multiplication.

just look at your answer!
how can (m+4)-(5+n) possible be 16m^2-25n^2 ????

should have been (4m+5n)(4m-5n)

in #8, first take out a "common factor" of 2, then you should see the difference of squares

8a^2-18
= 2(4a^2 - 9) = 2(2a+3)(2a-3)

again, how could your answer of
(7+ab)-(7-ab) possibly turn into 8a^2 - 18 ??? And where did the b come from ???