Please rewrite this question in an understandable form.
Answer:B
Step-by-step explanation:
Using what is known as the "Triangle Inequality Theorem" a+b can not be less than c or else it is not a triangle. (A and B are the smallest sides of the triangle).
A) 6cm + 15cm = 21cm which is less than 23cm: Not a triangle
B) 5cm + 9cm = 14cm which is greater than 13cm: This makes a triangle and therefore the answer is B
C) 5cm + 8cm = 13cm which is less than 13cm: Not a triangle
Answer:

Step-by-step explanation:
Completing the square gives

So we have to cancel the latter two terms out for the expression to always become a square (otherwise we are dealing with a square plus something else, which doesn't always result in a square), giving us our answer directly.
Answer:

Step-by-step explanation:
Ok, so we start off with 
Then, we subtract 2 from both sides so that becomes: 
After that, we simplify to get: 
Finally, the solution becomes: 