Answer:
It is the third one because of formula I² + 2I*II + II²
In your case I = 4x and II = 3
Answer:
Simplify the expression: 
Use the exponent power:

Apply the given rules;

Simplify:

then;

Therefore, the simplified expression of
is, 
Community property of addition because -6 + 6 would equal zero
Answer:
x = 9
Step-by-step explanation:
Rule: the two interior angles F and E when added, equal <FGH.
so
6x + 16 + 60 = 13x + 13 Combine the terms on the left.
6x + 76 = 13x + 13 Subtract 13 from both sides.
6x + 76-13 = 13x Combine
6x + 63 = 13x Subtract 6x from both sides.
63 = 7x Divide by 7
63/7 = x
x = 9