Answer:
yes Cecilia make her first mistake in step 2
Answer:
option C. 
Step-by-step explanation:
we know that
The volume of the triangular pyramid is equal to

where
B is the area of the triangular base
h is the height of the pyramid
In this problem we have


substitute in the formula

Answer:
For
, x = 2, or x = - 2.
Step-by-step explanation:
Here, the given expression is :

Now, using the ALGEBRAIC IDENTITY:

Comparing this with the above expression, we get

⇒Either (x-2) = 0 , or ( x + 2) = 0
So, if ( x- 2) = 0 ⇒ x = 2
and if ( x + 2) = 0 ⇒ x = -2
Hence, for
, x = 2, or x = - 2.