Answer:
Option (3).
Step-by-step explanation:
Option (1).
3(x - 1) = x + 2(x + 1) + 1
3x - 3 = x + 2x + 2 + 1
3x - 3 = 3x + 3 [Not True]
Therefore, this equation is not an identity.
Option (2).
x - 4(x + 1) = -3(x + 1) + 1
x - 4x - 4 = -3x - 3 + 1
-3x - 4 = -3x - 2 [Not true]
Therefore, this equation is not an identity.
Option (3).
2x + 3 = 
2x + 3 = 2x + 1 + 2
2x + 3 = 2x + 3 [True]
Therefore, this equation is an identity.
Option (4).

3x - 1.5 = 3x + 3 - x - 2
3x - 1.5 = 2x + 1 [Not true]
Therefore, this equation is not an identity.
Answer:
Step-by-step explanation:
Tienen 15 hojas de pegatinas en total.
Answer:Triangle A: 38 degrees
Triangle B: Unknown (not enough information)
Triangle C: Unknown (not enough information)
Triangle D: 70 degrees
Triangle E: 40 degrees
Step-by-step explanation:
f + 6 = ?
Well, the answer can be pretty much any number. It all depends on what number f is. f is a variable, so you can plug in any number to replace f.
For example, if f was 5, this is what the equation would look like:
5 + 6 = 11
If f was -3, this is what the equation would look like:
-3 + 6 = 3
So, again, the answer can be anything. It depends on what f is.