The answer is -8. Do you need an explanation?
Answer is A. 18
Because n + 18 =2n
Answer: Second option.
Step-by-step explanation:
It is important to remember the Distributive Property in order to solve this exercise.
The Distributive property states that:

In this case you have the following expression provided in the exercise:

Then, in order to write this expression in another way, you can apply the Distributive property. Multiply each number inside the parentheses by "t".
Applying this procedure, you get:

Notice that this expression matches with the one shown in the the second option.
900 : 1
The linear ratio = a : 30a = 1 : 30
volume ratio = 1³ : 30³ = 1 : 900
ratio of larger to smaller = 900 : 1
Use Pythagorean theorem (a squared is equal to c squared minus b squared)
Where a is the unknown leg, c is the hypotenuse and b is the known leg
a^2 = 13^2-5^2 which is 144
Then square root one hundred and fourty four to get rid of the power on a
Square root of one hundred and fourty four is twelve