Question

Which of the following are identities?

1.3(5 + 2x) = 15 + 6x
II.y = x + 3
III. x2 - y2 = (x + y)(x - y)
A. III only
B. I and III
C. II and III
D. I and II

Answer 1

I believe that the answer is 1

Explanation:

So an identity is an equation that both sides are equal. So in the first answer 3(5 +2x)=15+6x equals each other because after distributing the 3 into the (5+2X) it equals 15+6x

Answer 2

A

Explanation:

3(5 + 2x) = 15 + 6x

15 + 6x = 15 + 6x

6x - 6x = 15 - 15

0 = 0

No solution, no identity.

y = x + 3

No identity.

Identity : a² - b² = (a + b) (a - b)

The only identity is option 3.